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WHEAT FLOUR 
 
 ITS WEIGHT AND 
 MOISTURE CONTENT 
 
 BY 
 
 HARRY SNYDER 
 
 Prepared for and Published by 
 
 THE MILLERS NATIONAL FEDERATION 
 
 CHICAGO, ILL. 
 
TRIBUNE JOB PRINTING CO.. MINNEAPOLIS 
 
PREFACE 
 
 Many years ago the Association of Official Agricultural Chemists, 
 an affiliation of Chemists connected with the various agricultural 
 colleges and experiment stations, undertook to study and develop 
 methods for the analysis of foods and of agricultural products. A 
 method for determining moisture, seemingly a simple matter, was 
 one of the first subjects to receive attention. One giving reasonably 
 accurate, consistent and closely agreeing results was the goal, and 
 while substantial progress has been made, a full measure of success 
 has not been secured. Frequently the results have been con- 
 flicting and unexplainable, and analysts who have checked in other 
 determinations have failed to agree on moisture tests. This failure 
 has not been due altogether to lack of skill on the part of the chemist. 
 Methods for the determination of moisture in many foods have 
 never been fully perfected and seem to baffle all efforts for solution. 
 The necessity for accurate moisture methods is well known and 
 recognized by chemists. The Association from the beginning has 
 been engaged in most valuable and necessary work, that has not 
 been, at all times, as fully appreciated as it merits. Many of those 
 who have taken a prominent part are no longer active, and their main 
 reward has been the keen pleasure resulting from work well done. 
 But although much has been accomplished, there is still vital work 
 to be done. 
 
 For a number of years the writer of this article took part in the 
 cooperative testing of methods of the A. O. A. C. and has served in 
 various capacities in the organization, and for some years past has 
 been engaged in the manufacture of flour. A part of the data in 
 this article was presented in a brief prepared by request of the Bu- 
 reau of Chemistry, U. S. Department of Agriculture, in June, 1922, 
 and this more extended report is now made by request of the Millers' 
 National Federation. In each case the report has been made with- 
 out compensation. The brief and this more extended report have 
 been prepared in the hope that by bringing together certain phases 
 of the question, some solution of this much vexed problem may be 
 suggested. A number of chemists and others have read the proof 
 of this article and rendered valuable assistance. 
 
 Minneapolis, Minnesota. Harry Snyder 
 
 December 21, 1922. 
 
INTRODUCTION 
 
 The National Food and Drugs Act is a commendable type of con- 
 structive legislation and its faults, if any, are minor. The Secretary 
 of Agriculture is designated as the chief executive officer for the 
 enforcement of the act and of the authorized regulations which are 
 made by the three Cabinet Secretaries. The Bureau of Chemistry 
 is directed to make analyses and examinations of foods and drugs 
 in accord with the methods prescribed by the Association of Official 
 Agricultural Chemists, or by any method satisfactory to the Bureau. 
 The three Secretaries of the Cabinet have issued 31 regulations 
 (August, 1922) under authority of Section 3, and reserve the right 
 to alter or amend the regulations at any time. 
 
 From time to time the Secretary of Agriculture issues service 
 and regulatory announcements, and occasionally standards of purity 
 for food products. While these Standards, as the Department of 
 Agriculture states, do not have the force of law, they are issued "for 
 the guidance of trade and regulatory authorities and represent what 
 is recognized by best trade practices" as suitable standards. 
 
 In the enforcement of the Food and Drugs Act, certain practices 
 and methods of procedure are followed. The Service and Regu- 
 latory Announcements, the Standards for the Purity of Food Products 
 and the Methods of Analysis of the Association of Official Agricultural 
 Chemists are simply agencies which the Secretary of Agriculture uses 
 but they are not on the same legal basis as the Regulations made 
 by the three cabinet officers. 
 
 Nearly all states have separate food and drug laws and sometimes 
 they are not in harmony with the Federal laws and regulations. 
 Then, too, some states have laws that parallel or even go further 
 than the national law, in that all Standards of Purity of Foods 
 and other regulations issued by the National Secretary of Agriculture 
 are given the full force of law. 
 
 The miller does not object to reasonable rules and regulations but 
 only wishes to know what they mean, so as to comply with them. 
 Oftentimes he finds himself unable to understand the regulations, 
 particularly where different states interpret them diffisrently and 
 where officials have different ideas as to the interpretation of the 
 rules and regulations. 
 
 All laws, rules, regulations, standards and methods of analysis 
 are bound in time to be subjected to rigid tests as to accuracy and 
 they all must rest ultimately upon truth for their justification. 
 
CONCLUSIONS 
 
 1. Five thousand cars of wheat tested by the U. S. Department 
 of Agriculture gave moisture tests ranging from 7.4 to 22 per cent. 
 The flour milling tests showed that good strong wheat must be tem- 
 pered so as to carry up to 16% of moisture in order to be in proper 
 condition for milling. With normal humidity conditions during 
 milling, evaporation of water takes place so that the finished flour 
 usually contains less than i3}4% moisture, as determined by the 
 water oven method of drying. 
 
 2. Tests conducted by the U. S. Department of Agriculture show 
 that in the milling of wheat under good commercial practices, the 
 flours contained from 12.12 to 13.32% moisture. This is equivalent 
 to at least 13.12 and 14.32% moisture determined by the vacuum 
 method of drying at 100° C and 27 inches vacuum. 
 
 3. Flour constantly changes in weight and moisture content 
 according to the surrounding atmospheric conditions. It may dry 
 to 9.00% moisture and less, or absorb moisture so as to test 15.00% 
 or more; and the weight of the flour packages will vary accordingly. 
 
 4. Mechanical losses occur in handling flour that should not 
 be considered due to short weighing of the packages or form the 
 basis of a misbranding libel. 
 
 5. In a pile of flour the moisture content and weight of the 
 individual packages may vary quite widely. In the same pile some 
 bags may gain while others may lose moisture and weight. 
 
 6. Even in individual flour packages the moisture content is 
 never evenly distributed, rendering sampling of flour for moisture 
 tests extremely difficult. Different parts of a flour package may 
 vary .75% in moisture. 
 
 7. In calculating dry matter content of flour packages, appreciable 
 uncontrollable errors arise that must be taken into consideration. 
 
 8. The 13/4% moisture standard for flour was published in 1904, 
 about two years prior to the Food and Drugs Act. All commercial 
 moisture tests of flour at that time were made according to water 
 oven or air oven (100° C) drying methods. The U. S. Department 
 of Agriculture made flour moisture tests according to these methods, 
 and data used in formulating the 13^2% moisture standard was 
 obtained in this way. Also, the various official chemists used 
 quite extensively in their work the water or air oven method of drying. 
 
6 CONCLUSIONS 
 
 9. The Brown-Duvel method for the determination of moisture 
 in wheat is based on water oven drying. The moisture content of 
 wheat is taken into consideration in the federal grading of wheat, 
 and extra dry strong wheat always commands a premium when sold 
 on the market. In grinding dry wheat into flour the miller does not 
 "get something for nothing," or make a profit from added water. 
 Competition among the 7,000 or more commercial mills in the United 
 States is very keen, particularly with little or no export business. 
 
 10. The present ofiicial method for determining the moisture 
 content of flour is not accurate. The gluten proteins contain water 
 chemically combined, or water of hydration, which is not free moisture 
 but may be split off and included as such. Also mechanical losses, 
 due to the finer particles of flour being removed, occur in the vacuum 
 method of drying as the steady vacuum is maintained by the con- 
 tinual operation of a pump drawing a constant stream of air through 
 the oven. 
 
 11. The records of the Proceedings of the Association of Official 
 Agricultural Chemists do not show that drying foods in vacuo, as 
 it first appeared in Bulletin 46 Revised, was ever considered or tested 
 by the Association, or recommended by a referee either as a pro- 
 visonal or ofiicial method. 
 
 12. The Bureau of Chemistry formerly held that when flour was 
 packed full weight and without excess moisture and so long as it 
 remained in the original package and was sound and wholesome, it 
 complied fully with the Food and Drugs Act and subsequent devia- 
 tions occasioned by natural agencies were not a violation of the act. 
 
 13. Weight and moisture content are joint attributes of flour. 
 One cannot be considered without the other in weight adjustments 
 and this is featured in Regulation 26. 
 
 14. Flour originally packed with less than 13)4% moisture may 
 absorb moisture and temporarily contain 15% and not be unsound; 
 such flour should not be considered adulterated. The dry 
 matter content of a flour package remains reasonably constant, but 
 the difficulty is to control the factors which enter into its calculation. 
 
 15. For about 20 years the Association of Official Agricultural 
 Chemists did not designate any specific method as official for de- 
 termining moisture in flour and cereal products. There were official 
 methods for other foods and feeding stuffs but none for flour, and 
 drying in vacuo, as stated in Conclusion 11, was never adopted by 
 
CONCLUSIONS 7 
 
 the association for determining moisture in foods and feeding stuffs 
 as reported in Bulletin No. 46 Revised. 
 
 16. Chemists — official, industrial and commercial — get widely 
 divergent results when testing the same sample of flour for moisture. 
 Even when using the same method, the reults fail to check as closely 
 as is desirable. 
 
 17. Many European flours with which American flours come in 
 competition are milled with a high per cent of moisture. The Ameri- 
 can miller does not want a high moisture standard. He simply 
 desires that the standard shall not be changed by changing the method 
 of determining the moisture. 
 
 18. At the present time, there are inadvertently two flour moist- 
 ure standards, one (the old standard) based on the water oven, and 
 the other (the new standard) based on the vacuum oven method of 
 drying. The official method of drying "in vacuo" for determining 
 moisture in flour should be changed, or the 13^% water oven 
 standard for flour should be adjusted so as to mean the same today 
 as it did when adopted. When the conference was held with the 
 millers at Washington in 191 5, moisture testing of wheat and flour 
 were considered on a parity (water oven basis). 
 
 19. The "Standards of Purity for Food Products" issued before 
 the Food and Drugs Act was formulated and containing the 13}^% 
 flour moisture clause, were not authorized by congress for the guidance 
 of food officials and courts as is frequently stated. The first appro- 
 priation, 1902, carried such a clause but in the next and last act, the 
 1903-05 appropriations, this clause was not enacted. Circular No. 
 10 contains the only standards issued under the first act. There is 
 no standard for flour in Circular No. 10. Later standards promulgated 
 in 1904-06, after Circular 10 was issued, were formulated under an 
 act that did not carry any clause stating that the standards were 
 made for the guidance of food officials and courts of justice. 
 
 20. Moisture absorbed or lost during the filling of packages, and 
 uncontrollable deviations in manufacture due to sudden humidity 
 changes should be considered as reasonable variations which attend the 
 manufacture, filling and weighing of packages, conducted in compli- 
 ance with good commercial practice. The operative miller must have 
 a margin to cover such moisture changes so as to properly conduct 
 his milling operations, as every 10% change in relative humidity, 
 the U. S. Department of Agriculture finds, makes a difference of one 
 half of a per cent in the moisture content of flour. 
 
8 CONCLUSIONS 
 
 21. Some provision should be made whereby a miller can have 
 his flour weighed by accredited weighmasters and marked accordingly 
 so as not to be subject to libel actions because of uncontrollable 
 atmospheric conditions. 
 
 22. Redrying and repacking sound flour packed full weight and 
 with less than 13}4% water, because it has absorbed moisture from 
 the air, benefits no one except possibly those who are in the business 
 of drying flour or those who may desire to get flour siezed in order 
 to be released from contract losses arising from decline in the price 
 of flour. Conditioning sound flour is contrary to ordinary com- 
 mercial practices. 
 
 23. American flours tested in the open market containing up to 
 15% moisture have not been considered as adulterated by the Bureau 
 of Chemistry and such flours have received the Bureau's highest 
 commendation. "Owing to the firm attitude taken by American 
 millers, the adulteration of staple brands of flour is practically un- 
 known." Flours today contain no more moisture than when this 
 statement was made. 
 
 24. The Millers' National Federation, the Association of Opera- 
 tive Millers and the American Association of Cereal Chemists have 
 made certain recommendations relative to the moisture content and 
 weight of flour: that the method for moisture shall include only 
 the so called "free moisture" of flour, and in using the 13J/2 per cent 
 moisture standard for weight adjustments it shall be on the basis 
 of the moisture tests in vogue when the standard was formulated, 
 the idea being that the standard shall retain its original meaning. 
 
 25. It is believed that these organizations named stand for the 
 best trade practices on these questions and in no way would they 
 countenance either the adulteration or the misbranding of flour or 
 mill products as defined in the Food and Drugs Act. 
 
 American millers have almost invariably manufactured unadul- 
 terated flour and food products, dating from the time George Wash- 
 ington's flour, manufactured at Mount Vernon, was accepted in the 
 West Indies and other ports without inspection. The same idea 
 prevailed later when Abraham Lincoln worked in a flour mill and 
 received the appellation of Honest Abe. Throughout the period of 
 the Great World War the American millers, with the direction and 
 aid of Herbert Hoover, were able to meet and solve the most com- 
 plicated and colossal food problems the world has ever faced. 
 
WHEAT FLOUR 
 
 Its Weight and Moisture Content 
 
 /. Hygroscopicity of Flour, and its Effect upon Weight. 
 
 Flour as the term is ordinarily understood is a product of wheat, 
 and like wheat it is purchased and sold on a weight basis. A charac- 
 teristic quality of flour is hygroscopicity or the power to absorb 
 or discharge moisture according to circumstances. When flour 
 is handled, stored or transported in ordinary commercial ways it 
 may absorb moisture and increase in weight or it may dry out and 
 lose weight, according to the surrounding atmospheric conditions. 
 Deviations in weight and moisture content invariably occur, in 
 fact flour could not remain fixed in weight and moisture content unless 
 the atmospheric conditions as temperature, humidity, barometric 
 pressure and rate of movement of air currents always remained con- 
 stant. As hygroscopicity affects the weight and moisture content 
 of flour it must be considered in commercial transactions and allow- 
 ances must be made for its effect upon weight. 
 
 2. Water as a Component of Wheat and Flour. 
 
 Before considering the extent to which the weight and moisture 
 content of flour are influenced by atmospheric conditions, due to 
 evaporation or absorption of water, it is essential to consider water 
 as a natural component of wheat and flour. Water, as hygroscopic 
 or free moisture, is always present in wheat and flour. The extent to 
 which it ordinarily occurs and the moisture requirements of wheat for 
 milling as conducted in compliance with good commercial practice, 
 have been determined by the U. S. Department of Agriculture. 
 
 The following statement relative to the "Moisture Requirements of 
 Wheat for Milling Purposes," is copied from U. S. Department of 
 Agriculture Bulletin No. 788 (page 2), a professional paper on Mois- 
 ture in Wheat and Mill Products by J. H. ShoUenberger, grain super- 
 visor, in charge of milling investigations. 
 
 "Wheat when received at the mill is seldom, if ever, in the 
 best condition for milling, its moisture content being too high, 
 too low, or not properly distributed throughout the kernel. 
 To acquire the right moisture content for the outer and inner 
 parts of the kernel, thereby insuring the best possible milling 
 
lo WHEAT FLOUR 
 
 condition for different wheats, requires the application of various 
 methods of tempering. These methods may consist of a single, 
 or successive, or of combined applications of water, heat, or steam, 
 working through a period of time, ranging from a few minutes 
 to as much as 36 hours, in order that the moisture may be 
 properly distributed within the kernel. Dry climates and dry 
 seasons naturally produce wheat of low moisture content, and 
 damp climates and wet seasons produce wheat of high moisture 
 content. There is, moreover, often considerable range in the 
 moisture content of wheat during any given season and in any 
 one locality. Moisture determinations of samples obtained 
 from more than 5,000 cars of wheat, which were made by this 
 department at Kansas City, Mo., during the years 1910 to 1914, 
 inclusive, showed a range in the content of that factor from 7.4 
 per cent to 22 per cent. The fact that the moisture content of 
 wheat may vary so greatly is evidence that the problem of 
 properly tempering wheat is a complicated one." 
 
 To some who are not familiar with the process of flour milling it 
 might seem that the miller deliberately adds moisture to his wheat 
 so as to secure a greater weight of product. But a reasonable study 
 of the facts precludes such an inference. The miller is well aware of 
 the fact that excess moisture endangers the keeping qualities of his 
 flour and would entail a monetary loss. When flour becomes unsound, 
 invariably the miller must make good the loss, so he is not likely to 
 add any excess moisture that would endanger the keeping quality 
 his flour. For self-protection the miller wants to get away from all 
 possibilities of unsoundness. In fact, the miller is more desirous of 
 avoiding unsoundness of his flour than any one else, because in the 
 end he is the one who must make good any losses. However, he must 
 use water to condition his wheat for milling and this is, at times, a 
 process difficult to regulate. 
 
 J. The Tempering of Wheat Is a Recognized Necessity and a Long 
 Established Feature of Milling. 
 Any standard for moisture content of flour must necessarily recog- 
 nize that wheat is tempered before it is milled, and that the strong 
 wheats after they are brought into proper milling condition carry up 
 to 16% or so of moisture, depending upon the character of the wheat 
 to be milled. To mill hard wheats, the moisture content during 
 tempering and conditioning is leveled up or down to about 15% 
 (more or less). It makes no difference what the original moisture 
 content of the wheat may have been, if it is above this point it must 
 be lowered and if below, it must be raised. 
 
WHEAT FLOUR ii 
 
 When the miller buys his wheat the moisture content is considered. 
 If it is extra dry, the wheat commands a premium compared to 
 wheats with excess moisture. It cannot truthfully be said that the 
 miller buys wheats of low moisture content, adds water in the milling 
 process, and then sells the excess water in the flour, because the 
 moisture content is taken into consideration in the grading and 
 purchasing of wheat. The highest grade wheat is allowed 14% 
 moisture (as tested by the Brown-Duvel method) and other grades 
 proportionately more. The moisture standard for flour proclaimed 
 by the Secretary of Agriculture many years ago is 13)4%, maximum, 
 water oven standard, which is also the method used for standardizing 
 the "grain test". 
 
 At a comparatively recent date Food OfGcials have introduced a 
 different method for determining moisture in flour (vacuum oven 
 method) which secures a different per cent of moisture from the one 
 used in establishing the flour standard. Unwittingly, there are two 
 moisture standards : one based on water oven drying, and one based 
 on the vacuum oven method of drying. 
 
 If the miller buys top grade wheat with 14% moisture, and makes 
 this wheat into flour without gain or loss of moisture his flour tests 
 14% moisture according to the original water oven moisture standard, 
 and 15% or so according to the vacuum standard used by many food 
 officials. For some of the wheat grades, 15, 16 and 17% of moisture 
 are allcJwed, and often the miller purchases wheat with 4% more 
 moisture than is allowed in the flour. In a series of years the miller 
 buys as much wheat that averages above 13^% moisture as below. 
 
 The lack of proper application and use of technical data from 
 reliable sources have, no doubt, caused much misconception re- 
 garding this whole question of flour moisture. Fortunately, the 
 U. S. Department of Agriculture now has its own data upon this 
 question of moisture requirements for the milling of wheat and the 
 resultant moisture content of flour, and Food Officials should make 
 use of this data. A standard must rest upon exact experimental 
 data. Recognizing the necessity for the use of water in the tempering 
 of wheat in order to put it into proper condition for milling brings 
 us to the question of how much moisture should be left in flour 
 milled in compliance with good commercial practice. 
 
12 WHEAT FLOUR 
 
 4. Moisture Content of Flour Milled Under Good Commercial Con- 
 ditions. 
 
 The bulletin quoted in a preceding paragraph (U. S. Dept. of 
 Agr. No. 788) on Moisture in Wheat and Mill Products gives the 
 moisture content of the wheat before and after tempering and of the 
 various flour stocks resulting from the different reduction processes, 
 and also the moisture of the final flours from three commercial mills 
 in Kansas City. 
 
 Per Cent of Moisture 
 Mill I Mill 1 Mill 3 
 
 Wheat before Milling 12.40 13.90 14.04 
 
 Wheat after cleaning and tempering 16.00 13.80 14-67 
 
 Patent Flour 12.12 12.97 13-32 
 
 Clear Flour 12.88 13.01 13.22 
 
 "In the case of the wheat samples, their moisture content was de- 
 termined by use of the Brown-Duvel Moisture Tester, and in case of 
 the other samples (flour, feed, and other mill products), the method 
 used was that of drying to constant weight a small portion of the 
 sample in a water bath oven, at the temperature of boiling water." 
 
 This method of drying flour to determine the moisture (as 
 loss in weight) gives about 1% less water than the vacuum method 
 of drying at a relatively higher temperature and under conditions 
 which cause a greater loss in weight which is considered as moisture. 
 The vacuum method of drying cereal products for determining mois- 
 ture content is published in Methods of Analysis of the A. O. A. C, 
 September, 1920, a book copyrighted by the Association (Price 
 $5.00 per volume). In the preceding publication of these methods 
 by the Department of Agriculture (Bulletin 107, Bureau of Chem- 
 istry), no methods are given for the analysis of cereals (see page 
 59, which is a blank page except for a statement that the methods 
 are in preparation). During this interval and for several years 
 preceding, there was no official method for determining flour moisture. 
 
 This statement concerning water oven and vacuum oven drying 
 of flour and the difference in moisture results obtained by the two 
 methods must be taken into consideration in dealing with flour 
 moisture. 
 
 Had the vacuum method of drying, (extreme vacuum and high 
 temperature) as followed by some food chemists been used in these 
 tests the results would have been about 1% higher and approxi- 
 mately as follows : 
 
WHEAT FLOUR 13 
 
 Per Cent of Moisture 
 Mill I Mill 2 Mills 
 
 Patent Flour i3-i2 13-97 14-32 
 
 Clear Flour 13.88 14.01 14.22 
 
 All the flours except the patent of Mill i would, on the vacuum 
 standard, have exceeded the I3}4% moisture standard and been 
 considered adulterated and illegal. 
 
 Many years ago the Division of Chemistry of the U. S. Depart- 
 ment of Agriculture, made moisture tests of all the products of a 
 flour mill. These early tests formed the basis of the manufacturing 
 data for the formulation of the 13^ per cent moisture standard. 
 The moisture was determined by drying in an air bath. These 
 early tests and the later ones cited above, are on a reasonably com- 
 parable basis, as will be noted later. 
 
 There are certain features incident to the vacuum method of 
 drying to be considered later which cause the results to be 1% higher 
 than those obtained by water or air oven drying at 100° C. 
 
 For present purposes it is to be noted that in the tempering of 
 wheat and the milling of flour under good commercial practice, as 
 Bulletin No. 788 points out, from 12.12 to 13.32% moisture is left 
 in the flour as determined by the water oven standard or about 
 13.12 to 14.32 by the vacuum standard. 
 
 5. Weight and Moisture Content of Flour Are Inseparable Attributes. 
 
 In dealing with flour, it is necessary to consider weight and moisture 
 jointly, since a loss or gain of moisture causes a deviation in weight. 
 To consider weight and moisture as separate and unrelated attributes 
 is irrational and a violation of the laws of nature. A moisture 
 variation due to unavoidable evaporation or to the absorption of 
 water by packages in commerce, is a weight variation and is so 
 considered in Regulation 26 (3) — Rules and Regulations — Food and 
 Drugs Act. All standards must be applied in conformity to the 
 principles of the Food and Drugs Act and the authorized regulations, 
 and also be based upon good commercial practice. 
 
 A series of tests on the effect of the humidity of the air on the 
 moisture content and weight of flour were made by the U. S. De- 
 partment of Agriculture, Division of Chemistry about 1883. This 
 early and carefully conducted work of Richardson seems to have 
 been overlooked by rnany investigators, presumably because the 
 bulletin is out of print and unavailable. 
 
H 
 
 WHEAT FLOUR 
 
 Richardson exposed at Washington, D. C, five lots of flour for 
 1 8 days and made, at intervals, fifteen moisture tests on each flour. 
 
 Tables are given showing the original moisture content, that is 
 the moisture content at the beginning of the test, and "the weight 
 loo pounds of the original flour would have assumed under the con- 
 ditions named" when exposed in a room, with free access to the air, 
 "properly protected by a screen from exterior influences other than 
 air." 
 
 A resume of some of the data follows : 
 
 
 "rt'p 
 
 Weight 
 
 
 ea 
 
 ■si 
 
 pounds 
 
 Patent Flours 
 
 s 
 
 KK 
 
 
 
 7 
 
 
 ..100 
 
 
 8 
 
 46.4 
 
 100.65 
 
 
 lo 
 
 3S-0 
 
 99-53 
 
 
 II 
 
 59.0 
 
 101.73 
 
 
 12 
 
 60.1 
 
 102.68 
 
 
 13 
 
 34-0 
 
 99.88 
 
 Pillsbury A 
 
 14 
 
 
 101.08 
 
 Red River 
 
 15 
 
 48.2 
 
 101.53 
 
 Frazee 
 
 17 
 
 42.2 
 
 100.38 
 
 Pembina 
 
 18 
 
 S9-S 
 
 101.88 
 
 Minn. 
 
 19 
 
 60.1 
 
 102.03 
 
 
 20 
 
 55.6 
 
 102.48 
 
 
 21 
 
 51.8 
 
 101.43 
 
 
 22 
 
 51. 1 
 
 101.68 
 
 
 24 
 
 66.9 
 
 102.88 
 
 
 Moisture 
 
 content and 
 
 weight at 
 
 beginning of 
 
 Test, March 7-8 
 
 Weight original 
 
 100 lbs., 
 
 March 24th 
 
 100 lbs. 
 100 lbs. 
 100 lbs. 
 100 lbs. 
 
 9-48% 
 7.80% 
 
 7-85% 
 7-97% 
 
 TOO lbs. 13.68% 
 
 102.88 lbs. 
 104.87 lbs. 
 105.20 lbs. 
 105.95 lbs. 
 99.35 lbs. 
 
 The weight of the flour was dependent upon the relative humidity 
 of the air. When the humidity was low the flour weighed less and 
 with a relatively higher humidity the flour absorbed moisture and 
 increased in weight. In these tests of the U. S. Department of 
 Agriculture the weight and moisture content of flour are considered 
 as inseparable attributes. 
 
 6. The Dry Matter Content of Flour. 
 
 The establishment of a moisture standard likewise establishes a 
 dry matter standard, as dry matter is the product left after removal 
 of the free or hygroscopic moisture. Theoretically, the dry matter of 
 flour is reasonably constant and this is what should be considered 
 in dealing with weight. As long as flour is sound and wholesome, 
 the consumer is in no way defrauded if flour dries or absorbs moisture, 
 provided the flour was originally packed full weight and without 
 excess of moisture. On a dry matter basis such flours are neither 
 
WHEAT FLOUR 15 
 
 short in weight nor are they packed with excess moisture. When 
 flour dries, the moisture removed must in turn be added in bread- 
 making, and if the flour absorbs moisture from the air, then less 
 water is used in bread-making. In either case, the same amount of 
 bread, identical in dry matter content and nutritive value, is secured 
 from the same weight of original flour. 
 
 7. Factors Affecting the Dry Matter Determination of Flour. 
 
 After flour enters Interstate Commerce it is the dry matter that 
 must be taken as the basis of weight. Hence, it is important to 
 consider carefully the factors which affect the calculation of the dry 
 matter. A consideration of the basic principles upon which a dry 
 matter calculation must rest includes: 
 
 I. Correct weight of the package. 
 
 1. Drawing of a fair representative sample for moisture tests. 
 
 3. Determination of the moisture by an accurate method. 
 
 4. The moisture test should be made by a skilled chemist. 
 
 5. In calculating back to dry matter, all mechanical losses of 
 fine flour from packages during handling, transportation, and 
 storage must be precluded. 
 
 6. Minor oxidation or respiration changes during storage must be 
 considered. 
 
 Each of these factors may aff'ect the accuracy of a dry 
 matter calculation in flour. 
 
 8. Allowable Tolerances in Weighing Packages. 
 
 The Bureau of Standards of the U. S. Dept. of Commerce is the 
 weight authority in this country. On platform scales used indoors 
 for class A scales, a tolerance of two ounces per 100 pounds is allowed, 
 or one-eighth of 1%. (Circular 61.) Granted that the scale used 
 by a packer does not exceed the tolerance on beam for class A 
 scales, a flour packer (that is the person who weighs and packs the 
 flour) is liable to make either positive or negative errors in proportion 
 to his skill and ability to correctly use the scale. Let us call this the 
 human error. Regulation No. 26, Food and Drugs Act, allows for 
 discrepancies in weight which occur in packing conducted in com- 
 pliance with good commercial practice. 
 
 The U. S. Department of Agriculture has issued Bulletin No. 
 897 on weight variations of package foods, dealing with what are 
 considered maximum errors of good commercial practice on single 
 
1 6 WHEAT FLOUR 
 
 packages, and on the average of a representative sample. On a loo 
 pound package the error in weighing is calculated as 5.65 ozs. for 
 single packages and 2.92 ounces on the average of a representative 
 sample. "If other than freshly packed goods are weighed, allow- 
 ance must be made for shrinkage." 
 
 In arriving at these figures, the Bureau of Standard's tolerances 
 on scales are used. Of the suggested 2.92 ounces deviation on 
 one hundred pounds, average representative sample, 2 ounces are 
 allowed for the scales error and .92 ounce for the human error in 
 using the scales. It is proposed that the human error shall be less 
 than half of the scales error allowed by the Bureau of Standards. 
 
 Regulation No. 26 says that in allowing tolerances for packing 
 conducted in compliance with good commercial practice, the dis- 
 crepancy shall be as often above as below the marked quantity. 
 
 U. S. Department of Agriculture Bulletin No. 897 (Weight Varia- 
 tions of Package Foods) states that the marked quantity, or the 
 declared weight, must be used as the aim of the packer, and it suggests, 
 as explained, tolerances for deviations covering single packages and 
 for average representative packages; while Regulation 26 says the 
 discrepancy shall be as often above as below the marked quantity. 
 
 Regulation No. 26 ought not to obliterate the tolerance allowed 
 on scales as established by the Bureau of Standards, but the Regu- 
 lation as interpreted by Food Officials does so. Regulation No. 26 
 would seem to mean: discrepancies are allowed for errors, such as 
 human errors in weighing packages on scales which the Government, 
 through its Bureau of Standards, declares are suitable scales (class 
 
 A scales weighing 99 lbs. 15 oz., with an ounce tolerance either way, 
 is a Class A Scales. That is, when the weigher eliminates all human 
 error, he reaches 100 per cent accuracy, which is 99 lbs. 15 oz. on 
 this particular scales. In practice, however, some food officials claim 
 that when all packages are taken collectively the discrepancy must 
 be as often above as below the marked quantity and the average be 
 absolutely 100 pounds, omitting to consider that the weighings can 
 be made only as accurately as the scales permit. When this unusual 
 interpretation of Regulation 26 is made, then all tolerance allowed 
 by the Bureau of Standards on scales are obliterated, which would 
 not seem to be the intent of Regulation 26. 
 
 A reasonable interpretation must be made of the Rules and Regu- 
 lations. There seems to be an idea among some food officials that 
 only one weight tolerance is allowed on flour, that is (i) under Regu- 
 
WHEAT FLOUR 17 
 
 lation 26, and this tolerance is covered in Bulletin 897. The dis- 
 crepancies under (3), due to evaporation or to absorption of water 
 they think are included in the tables given in Bulletin 897, but this 
 is not the case. It is to be noted that (i) reads "Discrepancies due 
 exclusively to errors in weighing" etc., and (2) "Discrepancies in 
 weight," that is, after a package is weighed and enters commerce. 
 This (2) is confined to "differences in atmospheric conditions" in 
 various places. Regulation 29 mentions two distinct tolerances. 
 And there is no way these two tolerances can be considered as one and 
 made a lump sum tolerance. 
 
 9. Drawing Flour Samples for Moisture Tests. 
 
 As flour is hygroscopic, great care must be taken in drawing the 
 gross sample so that the three subdivisions forming the official 
 samples will actually represent the flour in question. Samples drawn 
 from the center and outer layer of a large flour package may vary in 
 moisture content to the extent of .75%. Constant changes in at- 
 mospheric conditions from day to day are reflected in the weight and 
 moisture content of flour packages. It takes time for all parts of 
 the package to become uniform in moisture content. 
 
 No directions are given in the A. O. A. C. methods for the selection 
 of samples of flour for purposes of analysis, as is done for many 
 products, such as cheese, sugar, fertilizers, etc. When a uniform 
 lot of flour is stored in a warehouse, some bags may gain in weight, 
 while others lose, which makes it extremely important as to what bags 
 are selected for sampling. The question of sampling is still further 
 complicated by the fact that borings of dry flour from the center of 
 a bag, exposed to a humid atmosphere, readily absorb moisture. 
 Atmospheric conditions must (always) be considered when sampling 
 flour. 
 
 Studies by Browne on the absorptive power of various carbo- 
 hydrates show that starch is exceedingly hygroscopic. Starch makes 
 up 70 per cent of flour. "While the absorptive power of the sub- 
 stances studied was highest in periods of high humidity and lowest 
 in periods of low humidity, no fixed relationship could be established 
 between rapidity of atmospheric fluctuations and the lag in the ab- 
 sorptive power of each material." (J. I. & E., Chem. Vol. 14, No. 
 8, p. 712.) 
 
1 8 WHEAT FLOUR 
 
 10. Are Present Methods for Determining Moisture in Flour 
 Accurate? 
 
 Comparative moisture tests on the same sample of flour have 
 been made by different chemists in co-operative testing work con- 
 ducted by the Association of Official Agricultural Chemists, the 
 American Association of Cereal Chemists and the American Institute 
 of Baking. The results of these tests fail to show consistent agree- 
 ment and it is a well known fact, often commented upon by chemists, 
 that many of the present methods employed for the determination 
 of moisture in flour fail to give accurate or consistent results. Even 
 with the vacuum method of drying, Official Chemists report a >^% 
 and more range in moisture content on the same samples when the 
 flour is handled in glass containers so as to preclude any effects of 
 humidity changes. 
 
 This lack of agreement of flour moisture results on the part of 
 different chemists cannot be said to be due entirely to lack of skill 
 of the chemist, but is largely due, as previously stated, to inherent 
 defects in the method used. These defects are discussed in detail 
 in another part of this report. As a matter of fact, as will be noted 
 later, there is no record in the early proceedings of the A. O. A. C. 
 that the vacuum method of drying foods for determining the loss of 
 weight as moisture was ever adopted either as a provisional or an 
 official method by the Association. 
 
 A regular progression of results are secured by the use of different, 
 methods for determining moisture in flour. The different methods 
 give reasonably closely agreeing results when always rigidly adhered 
 to in the same laboratory and in the hands of individual chemists, 
 "but agreement is not proof of accuracy." 
 
 //. Calculating TDry Matter Content from Weight and Moisture 
 Percentage Does Not Give Original Dry Matter Jl'eight As Packed 
 Where Mechanical Losses Occur. 
 
 Whenever flour is handled, mechanical losses occur. The men 
 who load cars, boats, or trucks are covered and coated with flour that 
 shakes through the imperfections in the containers and through the 
 needle holes that are made in sewing the bags. Rough handling 
 increases the mechanical loss. This should be adjusted separatelv 
 from short weighing of packages, because it is not short weighing. 
 When mechanical losses occur the miller gains nothing. It is not 
 
WHEAT FLOUR 19 
 
 my purpose to argue that the purchaser of the flour should bear 
 these losses, but the manufacturer should not be libeled when they 
 occur, and packages that have sustained mechanical losses should 
 not be used for calculating the dry matter of flour when packed. 
 Ten or more needle holes the size of a pencil point made when the 
 cloth was stitched and then stretched with the weight of the flour, 
 will permit an appreciable loss during a long rough voyage. Salt 
 in a shaker could not make such a trip without some loss, and flour 
 is much finer than salt. Such losses may at times be attributed to 
 excess moisture when packed, particularly if the package after sus- 
 taining such a loss were shipped into a humid region and absorbed 
 moisture in excess of 13/^%. Then, even if the flour failed to check 
 in dry matter, the analyst would not be justified in testifying that 
 the flour was manufactured with excess moisture. 
 
 In calculating the dry matter content of flour, a certain margin or 
 tolerance is always necessary to cover these variable and human 
 errors. Theoretically, the net weight of a package and the per cent 
 of water contained in the flour should give the necessary data to 
 calculate the dry matter content, but in actual practice the errors 
 that occur appreciably affect the final results and a close agreement 
 is not secured. 
 
 12. Calculated Dry Matter Content of Flours After Storage and Trans- 
 portation Compared With Dry Matter Content of Flours When 
 Packed. 
 
 The real test of the accuracy of the dry matter basis for judging 
 as to whether or not a flour package was filled full weight must rest 
 on carefully conducted tests. Such tests have been made by the 
 U. S. Department of Agriculture on corn meal and to a lesser extent 
 on flour. In the case of flour all of the tests and necessary data 
 have not been published so as to be available for a careful review 
 of the subject. The available data, however, suggest that appre- 
 ciable mechanical losses occur and there are also, at times, certain 
 chemical changes, such as respiration or oxidation processes that 
 influence weight. In the warehousing of flour, ventilation is ab- 
 solutely necessary, not only to remove excess of moisture, but other 
 products as well, so as to conserve the baking value of the flour. 
 Flour is not an inactive or chemically inert body when stored. 
 
 Briefly, a dry matter calculation of a flour package must rest upon 
 an accurate weight on a standardized scale and a reliable moisture 
 
20 WHEAT FLOUR 
 
 test, made by a skilled chemist who tests a carefully drawn and what 
 is known to be a representative sample, from which no mechanical 
 losses have occurred. Unless a dry matter calculation rests upon 
 such data, with reasonable tolerances, it cannot be accepted as 
 accurate. 
 
 We come now to another phase of the moisture and weight question 
 of flour. 
 
 /J. When Flour Is Packed FULL Weight and Without Excess 
 Moisture, Does It Not Comply With the Food and Drugs Act 
 Provided the Flour Is Sound and Wholesome and Is In Its Origin- 
 al Container? 
 
 This question was fully discussed at a Hearing in Washington, 
 D. C, June 5th and 7th, 191 5, before the full Standards Committee, 
 with Dr. Alsberg, Chief of the Bureau of Chemistry, presiding. 
 There were present, representative millers, bakers, department 
 solicitors and others. The record of the hearing, as taken by the 
 Bureau of Chemistry, shows that a mutual understanding was 
 reached. 
 
 Dr. Alsberg: "The necessity for this discussion arises from a 
 recent amendment to the Food and Drugs Act, which provides 
 that a statement of the quantity of contents shall be stated in 
 a plain and conspicuous manner upon a package of food in 
 package form. Now what are we, as Officers entrusted with 
 the enforcement of such a law, to do under the law with reference 
 to the marking of quantity of contents with an article like flour, 
 which by actual demonstration may run from 10 to 13}^% 
 moisture content?" 
 
 Governor Lind: "That is a question that has been put to me 
 professionally and I have said this: 'That every law must be 
 reasonably construed.' The direct application of that law is to 
 commodities or packages which inherently contain no factors 
 changing the weight. That law should not be invoked or applied 
 to a product which inherently, by reason of its chemical con- 
 stituents, fluctuates in weight from time to time, provided it 
 has been produced and packed under conditions which comply 
 with the law at the time of its packing. Here they have com- 
 plied with the law in manufacturing, packing, and marketing 
 or sending into the channels of commerce — flour. The fact 
 that flour may evaporate and change by reason of factors in- 
 herent in the commodity itself does not constitute a violation 
 of the law. If you take the other position, there is no safety 
 in a miller trying to do business a single day'. " 
 
WHEAT FLOUR 21 
 
 Dr. Alsberg: "I think that is a reasonable way of looking at 
 it and the law provides for tolerances— page 28." 
 
 Gov. Lind: "May I repeat in this connection a suggestion 
 I made the other day, which in my experience is part of the 
 construction or interpretation of every law? That (the law)^ can 
 apply only to commodities passing in interstate commerce that are 
 invariable in point of weight. In respect of products variable 
 in weight, the manufacturer's liability ceases when he delivers 
 into the hands of the common carrier. That is a delivery 
 under the law. When he delivers to the common carrier his 
 commodity, that is a delivery to the consumer and if at that 
 time it complies with the weight requirements, his full duty to 
 the law and society is performed. Subsequent variations are 
 of no concern to him. I am speaking solely from a lawyer's 
 standpoint." 
 
 Dr. Alsberg: "We feel that way about it. Governor, and that 
 is the reason why we have conducted a large investigation, 
 which will take years to complete, concerning the normal shrink- 
 age which takes place in shipping and transit, so that — " 
 
 Governor Lind: "You can reason back, yes." — ^page 126. 
 
 The record of this Hearing is unique in that the question of 
 weight and moisture content of flour was discussed so thoroughly 
 and by so many persons, all showing an earnest desire to reach a 
 correct solution and a workable understanding of this question. 
 
 It would seem that the principles enunciated and agreed upon at 
 this Hearing are logical and sound, and should prevail. They are 
 the views alike of the Department and of millers and represent the 
 best trade customs and practices relative to this question of weight 
 and moisture content of flour. 
 
 A careful study of the records of the Hearing show that there 
 was a general agreement of opinion that it was best not to make 
 any change in the 13}^% moisture standard which, as Dr. Alsberg 
 explained, was to be used for weight regulatory purposes. At that 
 time there was no official method for the determination of moisture 
 in flour, and the discussion must have been based on the methods 
 then in vogue. 
 
 14. tVhat Was the Prevailing Method or Methods in Use for Deter- 
 mining Moisture at the Time of this Hearing? 
 
 At that time the Brown-Duvel method for determining the moisture 
 content of grains had been developed by the U. S. Department of 
 
 ' Added by writer. 
 
22 WHEAT FLOUR 
 
 Agriculture and had been adopted and used by the trade generally. 
 This method is standardized against what is known as the water 
 oven method of drying; that is, the loss of weight which occurs when 
 the grain is dried in a water oven heated to the temperature of 
 boiling water. The loss of weight in drying is called the water or 
 moisture content. 
 
 At the Hearing, the moisture in the wheat and in the finished flour 
 were spoken of interchangeably. The millers, and members of the 
 Standards Committee and all who discussed the question spoke of 
 both the moisture in the wheat and in the flour often in the same 
 sentence, plainly showing that they were used on an equality basis, 
 and that one was strictly comparable with the other. Furthermore, 
 drying in a water oven and in an air oven at ioo° C. or so were the 
 only methods in common use at that time and they were the only 
 methods with which the trade was familiar. 
 
 As the Brown-Duvel method was used at that time for grading 
 wheat, it is inconceivable that the use of another method for deter- 
 mining moisture in flour, particularly one standardized on a different 
 basis and yielding different results could have been entertained by 
 the millers at this hearing. Wheat is 75 to 100% flour depending 
 upon the kind and quality manufactured and the moisture of the 
 flour, in or out of the wheat, should be determined by the same 
 standard. A double moisture standard for wheat and flour is not 
 commercially sound. 
 
 75. The Methods for Determining Moisture in Wheat and Flour 
 Should Be Retained on a Parity. 
 
 The necessity of having wheat and flour retained on a moisture 
 parity is so axiomatic that it would seem unnecessary to discuss the 
 subject. The Grain Standards Act provides for the establishment 
 of the method for determining moisture in wheat. The Brown- 
 Duvel method, as described in Circular 72 (Bureau of Plant Industry) 
 is the official method. The moisture can also be determined "or 
 ascertained by any device and method giving equivalent results" 
 (Sec. 4). Much care seems to have been taken in standardizing the 
 method so as to secure the free moisture present in the grain, as in 
 some cases the drying of the whole grain was continued for several 
 days. 
 
 This method of drying comes much nearer giving the actual 
 moisture content than the severe vacuum drying method followed 
 
WHEAT FLOUR 23 
 
 by some food officials. The Brown-Duvel method is standardized 
 on the same basis as the original 13^% moisture standard. Methods 
 developed or modified at a later date, giving higher results, have 
 virtually the effect of changing the moisture standard. Whenever 
 the method for determining the moisture content is changed, then 
 the standard should be changed to correspond. 
 
 16. The American Association of Cereal Chemists' Moisture Method. 
 The American Association of Cereal Chemists adopted about 3 
 years ago a method which is, in brief, drying in an air oven for 4 or 5 
 hours at about 103° C. This method is followed by many chemists 
 and, with minor modifications, is used in many official laboratories, 
 but gives different results from the A. O. A. C. vacuum oven method. 
 
 ly. Dejects of the Present Vacuum Oven Method for the Determination 
 of Moisture in Flour. 
 
 The present official method for determining the moisture content 
 of flour reads: "Dry a quantity of the substance, representing about 
 1 grams of dry material, in a current of dry hydrogen, or in vacuo 
 at the temperature of boiling water to constant weight (approxi- 
 mately 5 hours). If the substance be contained in a glass vessel, the 
 latter should not be in contact with the boiling water." This is in- 
 terpreted by some chemists to mean a temperature of 100° C, a 
 vacuum of 27 inches, and a prolonged period of heating. Water 
 boils in a vacuum oven at about 57° C. when the vacuum is 25 inches. 
 When the oven temperature is raised to 100° C, there is an excess of 
 43° C. over the boiling point of water. Under such conditions, a 
 greater loss occurs than when the flour is heated at the same tem- 
 pera turr in an air or water oven. 
 
 Heating in a vacuum oven for five hours, coupled with the 
 strong suction, may introduce three sources of error: 
 
 (i) Removal of chemically combined water from the proteins, 
 gliadin and glutenin. 
 
 (2) Mechanical losses. 
 
 (3) Minor losses from dissociation of other components of the flour. 
 
 18. Water of Hydration of the Wheat Proteins. 
 
 The presence of water in flour chemically combined as water of 
 hydration is determined and reported in U. S. Department of Agri- 
 culture, Bulletin loi, O. E. S. 
 
24 WHEAT FLOUR 
 
 "Water of hydration of wheat proteids. As previously stated 
 protein is calculated in these investigations by the factor 5.7. But 
 the product represents strictly anhydrous proteids, while the proteids 
 present in flour are not in that condition. When dried at 100° C. 
 the gliaden retained 4.22% water, which was expelled between 
 loi" C. and 102° C. and the glutenin retained 4.66% water which 
 was likewise driven off only with difficulty. It is difficult to separate 
 and obtain these proteids in a pure form without chemical changes. 
 From these facts and from results obtained with the bomb calorimeter, 
 as explained below, it would appear that as ordinarily present in 
 flour the gluten proteids are in fact in hydrated forms. 
 
 "The gluten proteids, gliadin and glutenin were prepared from 
 the gluten obtained in the separation of starch. The gluten was cut 
 into small pieces and extracted for several days with 70% alcohol. 
 The gliadin obtained from the alcohol extract was redissolved, 
 purified, and dried over sulphuric acid. Both the gliadin and glu- 
 tenin hold water very tenaciously and can be dehydrated only with 
 difficulty. The gliadin contained .34% ash and the glutenin .44% 
 which were taken into account in determining the heat of com- 
 bustion." The heat of combustion for gliadin is 5924 and for glutenin 
 5879 per gram. 
 
 Osborne in "The Proteids of the Wheat Kernel," states that after 
 purification with absolute alcohol, and ether he dried his proteins at 
 110° for analysis after he had first thoroughly dried them over sul- 
 phuric acid, and in the case of gliadin, the loss in drying was 
 equivalent to 9.2% water. He speaks of gliadin as not suffering 
 any change in the separation and preparation for analysis. 
 
 The possibility of the addition of water to the proteins during 
 extraction and of the water being held physically are precluded in 
 both Osborne's and Snyder's results. In both cases the proteins were 
 purified with absolute alcohol and ether and these reagents would 
 have removed any physically bound water. The 4.22% water found 
 by Snyder expelled at 103° C. and the 9.2% found by Osborne expelled 
 at 1 10° C. could come from no other source than the water chemically 
 bound with the protein. 
 
 After once passing no to 120° C. in an evacuated system, this 
 being the temperature beyond which water chemically combined 
 with the proteins is given off. Nelson & Hulett find (J. I. & Eng. C. 
 Vol. 12 No. i) flour can be heated, out of contact with the air, to a 
 comparatively high temperature before the point is reached where it 
 
WHEAT FLOUR 25 
 
 gives off appreciable amounts of gaseous products. It is not un- 
 reasonable to expect, after both the free and chemically combined 
 water are expelled, that a period of fairly stable equilibrium may 
 follow, when flour is heated out of contact with the air. 
 
 /p Mechanical Losses in Vacuum Jurying. 
 
 When the vacuum pump creates the vacuum, air is pumped out 
 of the oven. To maintain the vacuum, the pump must be kept in 
 constant action. The suction created removes fine flour particles 
 and these are counted as moisture losses. That such losses do occur 
 is easily demonstrated by passing the air as it leaves the oven through 
 a wash bottle containing distilled water. The wash bottle, acting 
 as a "dust collector," is placed between the oven and the pump. 
 The solution becomes cloudy and suggests milkiness. The micro- 
 scope shows flour particles in suspension. The amount of loss as 
 flour dust is difficult to determine as part sticks in the tubes and 
 dries like gum. 
 
 The writer of this article, in co-operation with Dr. Frankforter 
 of the University of Minnesota, has undertaken a study of the subject 
 of vacuum and other methods of drying. Our preliminary work 
 shows that it was necessary to make a special copper lining for the 
 vacuum oven to prevent flour particles lodging on the rough interior 
 walls. The mechanical losses are variable; at times they are small, 
 and then unexpectedly they are appreciably more and if the test is 
 prolonged they may make up .20% of a moisture test. Coarsely 
 granulated flour products, as grits, sufiisr less loss than the finest 
 granulated flour. 
 
 The main loss or error introduced in the extreme vacuum drying 
 of flour arises from the dislocation of the combined water or water 
 of hydration of the proteins. Applying Osborne's data, a flour would 
 yield an appreciable amount of water chemically combined with the 
 protein. 
 
 Mechanical losses, as flour particles sucked out by the vacuum 
 pump, as in vacuum cleaning, and water of hydration cannot be 
 considered as the hygroscopic or free moisture content of flour. 
 
 The use of strong vacuum and ioo°C for drying flour give results 
 that are inaccurate and too high and is an unwarranted inter- 
 pretation of the method. Vacuum drying was introduced with the 
 idea of securing drying at a low temperature so as not to induce 
 chemical changes in the substances dried. 
 
26 WHEAT FLOUR 
 
 The argument that the high vacuum drying of flour because it 
 secures maximum results, must be accurate, has no foundation. 
 
 This data, so far as the defects of the vacuum oven method of 
 drying are concerned, is introduced mainly to show why vacuum 
 oven drying gives higher results than water oven drying, and why 
 the U. S. Department of Agriculture, Bureau of Markets, in de- 
 veloping a method for determining moisture in wheat and other 
 grains gave preference to the water oven method. 
 
 The main question: What the 13K Per cent moisture standard 
 really means, is concerned only with the method employed in deter- 
 mining the moisture at the time the standard was formulated. As 
 will be noted in the following section, the standard was formulated 
 on the water oven drying method and not on the vacuum oven 
 method. At that time water oven drying was the method in use in 
 ordinary commercial practice. All standards must ultimately rest 
 upon the best commercial practices. 
 
 20. The Thirteen and a Half Per Cent Moisture Standard jor Flour 
 is Based on the Water Oven Drying Method. 
 
 The Standards Committee reported a definition for flour to the 
 Secretary of Agriculture, December 19th, 1904, nearly two j^ears 
 before the enactment of the Food and Drugs Act: 
 
 "Flour is the fine, sound product made by bolting wheat meal and 
 contains not more than thirteen and one-half (13K) per cent of 
 moisture, not less than one and twenty-five hundredths (1.25) per 
 cent of nitrogen, not more than one (i.o) per cent of ash, and not more 
 than fifty hundredths (0.50) per cent of fiber." (Bureau of Chemistry, 
 Bui. 69 (Revised) Part i.) 
 
 The data upon which this standard rests is published in Bulletin 
 No. 13, Part IX. The Prefatory Note to this Bulletin says: "The 
 examinations of flours had for their primary purpose the establish- 
 ment of a standard of composition. These analyses were made 
 chiefly in the years 1894 ^"^d 1895." They were made consecutively 
 with analyses mentioned in Division of Chemistry Bulletin No. 45, 
 issued April 15, 1895. This bulletin states: "Determination of 
 Moisture. Two grams of the substance in a flat bottomed alumi- 
 num dish are dried for five hours at the temperature of boiling water. 
 Experience has shown that after this time no further loss of weight 
 takes place." The analyses of the flours mentioned on page 7, 
 Bulletin No. 45, are all published for the first time along with other 
 
WHEAT FLOUR 27 
 
 flours, in Bulletin No. 13, Part IX. These two bulletins are in- 
 separable as far as the testing of flours is concerned. While no 
 specific mention is made of the moisture method in Bulletin No. 13, 
 the invariable rule is that when a connected series of tests are made, 
 as in this case, the method of testing is described in the first publi- 
 cation, and it is not changed in subsequent publications without 
 recording that fact. As the flour work in Bulletin No. 13 is a con- 
 tinuation of Bulletin No. 45, published in 1895 and at the time the 
 last flour work in Bulletin No. 13 was done, it is only necessary to 
 refer to Bulletin No. 45 to determine the moisture method employed 
 in this work. The water oven method that was followed is given in 
 this paragraph. 
 
 Bulletin No. 13 also gives eighty-eight "Analyses of Products of 
 Roller Milling," made by CliflFord Richardson of the Department in 
 1883-84. At that time a change was just beginning to be made 
 from the mill stone to the roller system of milling. The samples 
 were drawn from Pillsbury A Mill. Richardson's moisture method, 
 described in a preceding bulletin was: Flour "One gram was dried 
 in a porcelain crucible at ioo°-io5° C until it ceased to lose weight." 
 Richardson fully realized that flour manufactured by the mill stone 
 method was different from the product of the modern roller mill. 
 He mentions but does not use the earlier work as Brewer's, reported 
 in the tenth U. S. census (1880) and based largely on Kedzies' analy- 
 ses of mill stone flours in 1877. Such data could not be used in for- 
 mulating a standard without violation of Principle 7 governing 
 standards. "Standards are based upon data representing materials 
 produced under American conditions and manufactured by American 
 processes, etc." The "stone age" of milling does not represent 
 modern roller process milling. Richardson's analyses are not in- 
 cluded in the final averages of bulletin No. 13. 
 
 In addition to the 88 analyses of products of roller milling by 
 Richardson, and the 41 samples exhibited at the World's Columbian 
 Exposition, 81 samples of flour, including "flap-jack" and pancake 
 flours are reported in Bulletin No. 13. 
 
 The water oven method for determining moisture was used in all 
 of the new work upon flours published in Bulletin No. 13, where 
 "The examination of the flours had for their primary purpose the 
 establishment of a standard of composition." The reason for using 
 this method is stated in Bulletin No. 45 page 11. "Experience has 
 shown that there is practically no difference in the analytical data 
 
28 WHEAT FLOUR 
 
 secured in samples dried in the open air in a partial vacuum, and in 
 a current of hydrogen, and for this reason the drying in the air, 
 which is so much more easily accomplished, has been followed." 
 
 It is evident that if any other methods than water oven drying 
 had been used by the Bureau of Chemistry at this time they 
 would have been operated in such a way as to give the same re- 
 sults as the water oven method. 
 
 The average moisture content of the flours of Class I, reported in 
 Bulletin No. 13, Part IX, was 12.77 equivalent to 13.77 Per cent or 
 more on the basis of vacuum oven drying at 100° C and 25 inches of 
 vacuum. "The samples whose analyses are given under Class I may 
 be regarded as representing the best high-grade patent wheat flour 
 on our markets." See page 34 of this article. 
 
 Not only is the method used for determining the moisture 
 described but the analyst who did the work used air drying 
 many years later on products more susceptible to changes by air 
 drying than flour, namely fruits and fruit juices (See Section 26). 
 Open air drying was recommended and favored by the Bureau of 
 Chemistry at that time. Wiley in his "Principles and Practices of 
 Agricultural Analysis," Vol. 3, 1897, discusses the advantages aris- 
 ing from drying in open air at the temperature of boiling water on 
 page 34, and "there is left for the worker in the laboratory the choice 
 of processes already described, etc." p. 35. All of the data and 
 records show that "the choice of processes" was "drying in the open 
 air at a temperature not exceeding that of boiling water." 
 
 This is not a question as to the relative merits of analytical methods 
 for determining moisture in flour, it is simply a question as to the 
 methods used in testing the flours that were considered in formu- 
 lating the 133^ per cent moisture standard in 1904. It will be noted 
 later that water oven drying gives lower results than vacuum oven 
 drying 100° C and 25 inches vacuum. See Sections 28, 30 and 31. 
 The relative merits of white and whole wheat flours are noted 
 by Richardson who quotes Rubner's work that white flour is more 
 digestible and cheaper weight for weight than whole wheat flour: 
 "We can only hope, then, for an improvement in the character of 
 our wheats to add to their nitrogen content, and to improved 
 methods of milling, which we are fast becoming possessed of, to 
 make it possible to produce flour with the highest amount of 
 nitrogen in the higher grades, and at the same time with it the 
 best physical condition. Then we may expect to improve our 
 breads." 
 
WHEAT FLOUR 29 
 
 21. Drying Foods in Vacuo at ioo°C and 2^ inches Vacuum for the 
 Determination of Moisture was never adopted as an Official Method. 
 
 The present official method, as previously stated, first appeared 
 as official for cereals in the A. O. A. C. Methods, published in 1920. 
 The preceding publication of the Methods by the Government in 
 1908 (Bulletin 107) gave no methods for cereals. 
 
 The methods for 1920 were read and all new methods were acted 
 upon by the Association. Any claim that the vacuum method ot 
 drying (with heat) is official rests upon its having been published as 
 official in Bulletin 107 "V General methods for the Analysis of Foods 
 and Feeding Stuffs," page 38. 
 
 As early as 1899 (See Bulletin 56 — page 129) a division of Cereal 
 Products was created entirely separate from the division of Cattle 
 Feeds and special methods for their testing were contemplated. 
 
 See also Provisional Methods A. O. A. C. for the Analysis of Foods, 
 Bulletin 65 Bureau of Chemistry, page 41. 
 
 IV. — Cereal Products 
 by A. McGill 
 
 Chemist of Inland Revenue Lab. Ottawa, Can. 
 
 "It has been found impossible to prepare the report on this 
 subject this year. The heading has been inserted here to pre- 
 serve its proper order." 
 
 It was generally recognized by the Association that there were 
 no official methods for testing cereals, after this subdivision had 
 been created. See Proceeding A. O. A. C. 1910, Bulletin 137,^ page 
 119 "Cereal Products." 
 
 "It is recommended — 
 
 (i) That the associate referee on cereal products be instructed 
 to devote special attention to methods for analyzing and testing 
 wheat and flour. 
 
 Carried. (Included in supplementary report of committee C. 
 Attention was called to the fact that no methods for cereal 
 products are given in Bulletin No. 107, Revised, and that milling 
 and baking tests were also needed.)" 
 
 "Water in Foods." 
 
 "It is recommended — 
 
 (i) That the vacuum method for the determination of moisture 
 
 in foods be further studied, etc." 
 
3° 
 
 WHEAT FLOUR 
 
 Numerous other references could be given showing that the associ- 
 ation recognized that there were "no methods for the analysis of 
 cereal products." 
 
 Referee White in his report to the A. O. A. C. for 191 1 recom- 
 mended: 
 
 I. "That the method for the determination of moisture in Bul- 
 letin 107, revised, page 38 (i), be made official for cereals." (Also 
 vacuum dessicator method was recommended for further study.) 
 
 For purposes of comparison, this method and the method of 1920 
 are both given. The precaution as to drying, common to each method 
 is omitted. 
 
 From Bulletin 107 Revised 1908. 
 
 "Dry a convenient quantity 
 of the substance representing 
 about 2 grams of dry material, 
 at the temperature of boiling 
 water until it ceases to lose 
 weight (approximately five 
 hours), in a current of dry 
 hydrogen or in vacuo." 
 
 This method was official for 
 Foods and Feeding Stuffs, but 
 did not include flour. 
 
 From Method of Analysis A. O. 
 
 A. C. 1920. 
 "Dry a quantity of the sub- 
 stance, representing about 2 
 grams of dry material, in a 
 current of dry hydrogen or in 
 vacuo at the temperature of 
 boiling water to constant 
 weight (approximately five 
 hours). 
 
 This method is now official 
 for Foods (including flour) 
 and Feeding Stuffs. 
 
 The "in vacuo" moisture test for flour and cereal products now 
 becomes linked with the method for Foods and Feeding Stuffs, and 
 its claim as official for flour rests with the original action taken in 
 regard to this method. 
 
 Drying in vacuo, printed in the Official Methods, first appears in 
 Bulletin No. 46, Revised Edition 1898, page 23: "Dry from 2 to 
 3 grams of the substance for five hours, at the temperature of boiling 
 water, in a current of dry hydrogen or in vacuo." In the first 
 edition of bulletin No. 46, published in 1895, (i^ot the revised edition,) 
 the sentence ends with hydrogen. 
 
 Therefore the status of drying "in vacuo" rests upon whatever 
 action was taken by the A. O. A. C. between 1895 and 1898, as 
 drying "in vacuo" does not appear in the 1895 but does appear in 
 1898 methods. 
 
 Let us first consider how a method becomes "official." To become 
 official a method must be subjected to the following tests, according 
 
WHEAT FLOUR 31 
 
 to the preface in "Methods of Analysis A. O. A. C," published in 
 1920. 
 
 "To attain the aims of the association for a set of accurate 
 methods, a system was evolved by which the methods in question 
 are subjected to the most rigorous and painstaking scrutiny 
 before they can be adopted. A "referee" is appointed for any 
 subject for which the association has not yet an official method 
 or for a method which seems to require further investigation. 
 The referee conducts analyses according to the methods sug- 
 gested for adoption in comparison with methods already estab- 
 lished, obtaining the collaboration of as many as possible of 
 the workers in that field. In addition, a great deal of original 
 research has been inaugurated on new methods. This system 
 developed logically until at the present time, in order to be 
 adopted as "tentative," a method must be recommended to the 
 association by the referee, and such recommendation is made 
 only after the method has undergone a thorough collaborative 
 and critical study. Further, the special committee on methods 
 must approve the recommendation and the method must be 
 accepted by a vote of the association. In order to become 
 "official," a method must be again accepted at another annual 
 meeting. The recommendations of referees are published in the 
 reports of the proceedings of the association in the Journal of 
 the Association of Official Agricultural Chemists, so that all 
 tentative methods are made public before being adopted. This 
 permits consideration and criticism by chemists who are not 
 members of the association. It is immediately apparent that 
 a method can be made official only after the most thorough 
 series of tests, not alone for accuracy, but for ease of operation 
 as well. It may be stated without reservation that more elab- 
 orate and painstaking effort has been expended on this collection 
 of analytical methods than upon any other set of similar methods 
 in the field of chemical science." 
 
 This Preface is signed by C. L. Alsberg, Secretary of the 
 Association of Official Agricultural Chemists. 
 
 Did this "or in vacuo" method follow the usual channel of adoption ? 
 
 How and when was drying in vacuo made official.'' 
 
 No mention is made in the Proceedings of the Association of Official 
 Agricultural Chemists for the years 1895, 1896, 1897 or 1898 of the 
 vacuum method of drying having been tried, proposed as a provisional 
 method, or finally adopted as an official method. 
 
 I have all of these reports. I have examined them carefully, 
 and so have other chemists; the only way in which vacuum drying 
 is mentioned is in connection with Carr and Sanborn's paper (1895) 
 
32 WHEAT FLOUR 
 
 page 134 on "The Dehydration of Viscous Organic Liquids." In 
 the discussion following the paper Dr. Wiley aptly states: page 152. 
 
 "I would like to suggest the importance of drying at low temper- 
 atures. In drying levulose at the temperature of boiling water 
 in the open air, there is a progressive decomposition of the 
 substance, so that the apparent amount of water obtained is 
 much greater than the real percentage of water present. In 
 the drying of honeys, low-grade sugars, and molasses of all 
 kinds, the error is a very important one. It seems to me that 
 the official method should be changed when the proper time 
 comes to include possibilities of that kind. It is easy to dry in 
 a partial vacuum, and it seems to me that all organic liquids, 
 whether viscous or not, and all organic bodies for chemical 
 examination or for the determination of moisture should be 
 dried in partial vacuum. There would be no danger of oxi- 
 dation by the proposed method; the drying could be accomplished 
 more regularly and with less danger of injury to organic sub- 
 stances. Better results could be obtained by adopting a method 
 which would include the good points of all." 
 
 In the 1896 report, Lindsey,, referee on Cattle Feeds, mentions 
 that he had discontinued "comparisons of results obtained by different 
 analysts in determinations of moisture, crude ash, fiber, fat and pro- 
 tein. He believes these methods to be as perfect as they ever can 
 be made, XX." Page 46. In the 1897 report no comparative 
 tests for moisture by vacuo are given nor is there any indication 
 that any such studies or tests were made. Provision is made for 
 republication of methods, on page 153. There are no recommend- 
 ations for any changes in moisture determinations in Foods (then 
 known as Cattle Feeds). 
 
 In the 1898 report Krug, referee on Cattle Feeds, gives the moisture 
 content of the three samples used in the estimation of starch. These 
 results are only incidental and no mention is made of methods em- 
 ployed. It is stated on page 88 that the Carr and Sanborn method 
 had been provisionally adopted by the Association for water in sugar 
 and molasses, but had not received much attention from the associa- 
 tion chemists. 
 
 The Methods of Analysis A. O. A. C. bulletin 46 (revised), bears 
 this legend on the title page: 
 
 "Adopted by the Association of Official Agricultural Chemists 
 November 11, 12 and 14, 1898." 
 
WHEAT FLOUR 33 
 
 There is no record in the 1898 Proceedings that these Methods of 
 Analysis were ever reported to, received, discussed, adopted or acted 
 upon by the Association. 
 
 It is in the 1898 methods that vacuo first appears printed in the 
 official methods. 
 
 The records of the Association of Official Agricultural Chemists 
 do not show that drying foods in vacuo with heat as applied to the 
 division of Foods and Feeding Stuffs was ever even considered or 
 tested by the Association or recommended as a provisional method 
 or finally adopted as an official method. 
 
 Had the method been tested first as provisional like other official 
 methods, its failure to give results would have been observed, and 
 the time, temperature, and vacuum conditions would have been 
 studied. 
 
 22. Drying in Vacuum Without Heat. 
 
 Method No. 2, for moisture in Foods and Feeding Stuffs, official, 
 page 71 (Methods of Analysis A. O. A. C) was developed by Dr. 
 Trowbridge who recommended it for general use in the analysis of 
 foods, except factory control when rapidity is necessary. Dr. 
 Trowbridge states: "Most food products undergo more or less 
 change upon being heated for several hours at 105° C even if it is 
 done in a vacuum or in an atmosphere of hydrogen." Page 150, 1909 
 A. O. A. C. Proceedings. This method was regularly adopted by 
 the Association. 
 
 High tempera,ture vacuum drying was not the original intent when 
 vacuum drying was introduced. The whole idea was to avoid high 
 temperature, and to get the moisture without heating to 100° C. 
 When "or in vacuo" was placed on the end of the sentence, 1895 
 Methods, it meant that vacuum drying was a new method and it 
 was separate and distinct from hydrogen drying and the conditions 
 different from those governing hydrogen drying. It was first drying 
 in hydrogen, if the analyst elected to do so, or if he did not dry in 
 hydrogen he could dry "in vacuo" without temperature or pressure 
 restrictions. Without these limitations chemists have failed to 
 get concordant results. 
 
 23. To What Extent do Flours Range in Moisture Content? 
 
 A flour that is manufacturfed with not to exceed 133^ per cent mois- 
 ture and packed full weight may gain or lose in weight and moisture 
 
34 WHEAT FLOUR 
 
 content according to the prevailing atmospheric conditions where 
 the flour is stored. In Bulletin No. 13, previously mentioned, the 
 moisture content of the flours ranged from 9.39 to 15.30 per cent for 
 the first class of flours, and for other classes 9.28 to 15.71 without 
 being considered adulterated, as extracts from the bulletin show: 
 
 "Discussion of Results — Class i. 
 
 "The samples whose analyses are given under Class i may be 
 regarded as representing the best high-grade patent wheat flour 
 on our markets." Page 1257. 
 
 "Moisture. 
 "In the samples of Class i there is an extremely uniform per- 
 centage of moisture. The variations from the mean, which is 
 12.77 are usually very small. The extreme plus variation is found 
 in sample No. 12549 with a content of moisture of 15.30 per cent, 
 the variation being 2.52 per cent in this case. The minimum 
 percentage of water is found in sample No. 12992, containing 
 9.39 per cent, a variation from the mean of 3.38 per cent." 
 
 "The data show that the flours of this grade are placed upon 
 our markets under very uniform conditions in respect of moisture 
 This arises either from the fact that the quantity of moisture 
 in the grains from which the flours are made is remarkably 
 constant, or that the flours when prepared exhibit equal hygro- 
 scopic properties which tend to regulate the quantity of moisture 
 therein contained. The only marked variations from the mean 
 percentages of moisture are found in the two samples mentioned 
 above and in No. 10834. Leaving out of consideration these 
 three samples, the remarkable uniformity of moisture is made 
 more strikingly apparent." 
 
 \, Following the suggestion that is made to omit the three extreme 
 samples, 
 
 No. 12992 with 9.39% moisture 
 No. 12549 with 15.30% moisture 
 No. 10834 with 14.06% moisture 
 
 It is interesting to observe some of the results recorded for flours of 
 the "best high-grade patent wheat flours on our markets" as recorded 
 on page 1254 and of Class 11 designated as flours "having a compo- 
 sition not very greatly different from the high-grade patent flours 
 already mentioned." 
 
 No. 10841 with 13.68% moisture 
 No. 10843 with 13.69% moisture 
 No. 10862 with 13.93% moisture 
 
WHEAT FLOUR 35 
 
 No. 1 1 898 with 13.62% moisture 
 
 No. 10822 with 13.71% moisture 
 
 No. 10833 with 13.57% moisture 
 
 No. 12547 with 13.93% moisture 
 
 It is to be noted that these flours as well as half a dozen others 
 that were tested are above 13}4 per cent moisture content. In 
 fact flours up to 13.93% moisture are given, and they are stated 
 to have a remarkable uniformity of moisture. There is no suggestion 
 of any unusual content of moisture until a sample with 14.06 is 
 reached. 
 
 As previously noted these results are all on open air basis of drying. 
 
 24. Flours with 75 per Cent Moisture not considered Adulterated. 
 
 The Bureau of Chemistry regard from 9 to 1 5 as the normal range 
 for the moisture content of flour. In the 14th Convention (1897) 
 of the A. O. A. C. Dr. Bigelow of the Bureau of Chemistry, as Referee 
 on Food Adulteration, in discussing the adulteration of flour says: 
 "Its water content may be too high and cause it to be adulterated." 
 He gives a table showing the range of composition for first class 
 flour samples (page 117): 
 
 
 Maximum 
 
 Minimum 
 
 Moisture 
 
 15- 
 
 9- 
 
 Ash 
 
 .8 
 
 .3 
 
 Proteids 
 
 15- 
 
 8. 
 
 Fiber 
 
 I. 
 
 .1 
 
 Ether Ext. 
 
 2. 
 
 .5 
 
 N free Ext. 
 
 90. 
 
 82. 
 
 Figures are also given for various "cereal flours and meals." Dr. 
 Bigelow, who did many of the flour analyses reported in Bulletin 13, 
 according to the prefatory note, says: "It must be understood that 
 this table is only provisional, and it will frequently happen that 
 products which are not adulterated will not fall within these limits. 
 At the same time it is believed all samples of first class flour and meal 
 should do so." 
 
 It is quite evident that the Bureau of Chemistry regarded 9 to 
 15 per cent as normal ranges of moisture in flour samples found on 
 the market. 
 
 The American flours tested by the Bureau of Chemistry have 
 
36 WHEAT FLOUR 
 
 from time to time been highly commended because of their freedom 
 from adulteration. Bulletin No. 63, page 10 says: 
 
 "Flour. Owing to the firm attitude taken by American millers, 
 the adulteration of staple brands of flour is practically un- 
 known.***" 
 
 The flours today contain no more water than when this statement 
 was made. 
 
 It has been suggested that when flour absorbs moisture in excess 
 of 13^%, spoilage occurs. Fourteen and one-half vacuum stan- 
 dard is only about 13^ water oven standard; hence the spoilage 
 point on the vacuum basis would be, above 143^. Spoilage may take 
 place independent of any specific moisture content, depending upon 
 the conditions of storage, germ content of flour, and condition ot 
 the wheat when milled. When spoilage does occur the Food and 
 Drugs Act can be invoked independent of moisture content. 
 
 Corn meal has a 14% moisture standard and it is well known that 
 corn meal has poorer keeping qualities than white flour. If the 
 standards reflect keeping qualities then corn meal should have less, 
 and not more, moisture than flour. 
 
 25. Moisture Content of Foreign Flours. 
 
 Foreign flours contain more water than American flours. This 
 point was brought out at the Washington Hearing in 1915. Data 
 upon this point are also recorded in Bulletin No. 13, page 1267, rela- 
 tive to the composition of typical French flours. These type samples 
 contained respectively 15.42, 14.92, 15.58 and 14.74 Per cent moisture. 
 Other than cellulose and sucrose, it is stated: "In respect of the 
 other constituents it may be said that the percentages obtained 
 agree quite well with the results of the general analyses which have 
 been conducted in this division." Page 1269. 
 
 The American Miller does not desire nor ask for a high moisture 
 standard. His desire is to have 12}4 per cent moisture mean the 
 same now as it did when the standard was formulated. Then wheat 
 and flour moisture methods remain on a parity. 
 
 26. Vacuum and Hydrogen Drying not Followed in Official Laboratories. 
 
 At the time the 133^ per cent moisture standard was formulated, 
 comparatively few of the official laboratories of the United States 
 dried food products in any other way than with the water or air 
 bath. 
 
WHEAT FLOUR 37 
 
 W. H. Krug, Referee on Cattle Feeds in 1 901, states on page 46, 
 "The official methods for analysis of foods direct that the material 
 shall be dried for five hours, at the temperature of boiling water in 
 a current of dry hydrogen, or in vacuo. Neither of these methods 
 has been generally adopted, as most laboratories are not equipped 
 with the necessary facilities and are thus forced to use some other 
 method." Frequently the Referee directed the analyst to determine 
 moisture by the methods given in Bulletin 46 "or according to the 
 methods used in your laboratory stating the method employed." 
 Such directions were continued down to the report given in the 
 Journal, A. O. A. C. for August 15, 1920. 
 
 Drying at the temperature of boiling water was for years the 
 standard and common method in use for determining moisture in all 
 foods. A good illustration is given in the Seventh Convention, 1890 
 Report, page 56, in discussing butter. 
 
 "Mr. Lupton asked whether the temperature was stated in the 
 recommendation. 
 
 "Mr. Wiley said that it was; the temperature was fixed at the 
 boiling point of water, the standard temperature adopted by the 
 Association. Comparing Colorado with Louisiana, the difference in 
 temperature would be very considerable, but the rate at which water 
 went off from a substance depended generally upon the pressure and 
 the temperature, and boiling water gave a constant condition every- 
 where, so with that as a standard all worked under the same conditions 
 although there was a difference in actual temperature." 
 
 In 1902 Dr. Bigelow of the Bureau of Chemistry (Bulletin 66, page 
 11) states: 
 
 "The drying of the samples in vacuo was not considered prac- 
 ticable, as few laboratories are equipped to use the method, and 
 the large bulk of work also prohibited it." 
 
 In the 1907 Proceedings 53 analysts give moisture tests of portions 
 of the same sealed sample sent out for purposes of testing. Five 
 analysts used the vacuum method, only one above 75° C or so, eight 
 used hydrogen drying, and the remainder, 40 out of the 53, used 
 either the water or air bath or failed to report the method they used. 
 Evidently some did not wish to go on record as to the method used. 
 
 Neither vacuum nor hydrogen drying represented methods in 
 
38 WHEAT FLOUR 
 
 general use in official laboratories preceding the time the 13^ 
 per cent flour moisture standard was formulated or at the time the 
 Food and Drugs Act was passed. During all these years trade 
 practice has been based on water oven and air oven methods of 
 drying. 
 
 2y. No Short Weighing of Flour or Excess Moisture should be Enter- 
 tained. 
 
 Suggestions for continuing the moisture methods used for establish- 
 ing the 133^ per cent flour standard cannot be construed as suggesting 
 that any short weighing in filling flour packages is to be entertained. 
 All flours should be packed full weight, net 196 pounds per barrel, 
 except when state laws require a different weight. In arriving at the 
 net weight declarations of packages, in no case is more than i2}/2 
 per cent moisture to be allowed as determined by the open air methods 
 in use and approved by the Division of Chemistry U. S. Department 
 of Agriculture at the time the data for this 133^ per cent moisture 
 standard was made. 
 
 This is the essence of the 13^ per cent standard as understood 
 by the millers at the 191 5 Hearing and as expressed by a number 
 of millers as the record of the minutes of the Hearing show. 
 
 From Page 126 of Record of Hearing: 
 
 Mr. Moses: We have various wheats. I don't think any 
 miller should be permitted to pack less than 196 pounds to the 
 barrel. 
 
 Dr. Alsberg: Well, of course, we are not concerned with 
 the miller's contract. We are concerned with this phase of 
 the thing : That the law says that food in package form shall 
 bear upon the outside of the package a plain conspicuous state- 
 ment of the quantity of contents. How that statement shall 
 be made is the only question we are considering. 
 
 From Page 125, condensed from a statement of Mr. Lingham.**** 
 "Some of us millers realize that you are trying to formulate some 
 definite basis of arriving at the actual flour content of packages. 
 We believe that some basis of moisture must be adopted. I am 
 speaking for myself more particularly. ******and for myself I 
 believe that 13^^ per cent moisture content would be accepted as a 
 moisture content basis and all weights figured and determinations 
 from that basis up or down." 
 
WHEAT FLOUR 39 
 
 The parts omitted relate to low moisture content flours which are 
 now considered: As to the miller who might mill flour with ii per 
 cent moisture content, that phase of the question was fully discussed 
 and was summarized by Mr. Crocker in reply to a hypothetical 
 case of milling wheat with less than 7 per cent moisture propounded 
 by Dr. Alsberg. 
 
 "Mr. Crocker: Assuming that this miller could turn out a 
 flour with II per cent moisture content, on what basis is he 
 supposed to grind that flour? If the wheat he buys is corres- 
 pondingly lower he should put in 196 pounds. If he is turning 
 out flour with 10 or 11 per cent moisture content the assumption 
 is that he is buying his wheat correspondingly. Really he is 
 on the same basis with the other miller. 
 
 Briefly, the miller who mills his flour v/ith 11 per cent moisture 
 and buys his wheat with 7 to 9 per cent moisture, has no claim for 
 packing a barrel of flour to weigh 191 or 192 pounds. The miller 
 who buys wheat with 15 per cent moisture and is compelled to pack 
 his flour with 13^ per cent moisture has a greater moral claim for 
 packing flour with 15 per cent moisture than the miller who buys 
 wheat with 7 per cent moisture and leaves 11 per cent in his flour. 
 But this is all an academic discussion and fails to represent present 
 commercial conditions. The way wheats are now graded and 
 handled, if the dry wheats have the requisite quality they invariably 
 command a premium in proportion to their dryness, and the extreme 
 wet wheat sells at a lower price, as discussed in paragraph 3 of this 
 article. 
 
 There is no alchemy in milling. There are over 7000 commercial 
 mills in the United States capable of making, in about 100 days, 
 flour that will last this country one year. There is no way a miller 
 can get something for nothing and make a profit. As soon. as a 
 sound dry strong wheat is found it always commands a good stiff 
 premium. Food Officials do not realize the keen competition that 
 exists in the milling trade and the impossiblility of any miller putting 
 out adulterated (with water) or a misbranded (short weight) flour 
 and being able to "get by" or sell such an article to his trade. The 
 flour trade is too sensitive and competition too keen to permit such 
 practices being carried to any appreciable extent and the Millers 
 National Federation and other trade organizations would soon expose 
 any such practices. 
 
40 
 
 WHEAT FLOUR 
 
 28. Results of the First Co-operative Tests A. 0. A. C. with Drying 
 Flour in Vacuum Oven and in Water Oven. 
 In a preceding paragraph it is mentioned that in 1910 the A. O. 
 A. C. directed that a study be made of the methods for testing cereal 
 products. Associate Referee White of North Dakota made such 
 studies and reported the following results in 191 1. These results 
 are interesting to note. 
 
 "RESULTS OF ANALYSIS.— MOISTURE. 
 
 Comparative results obtained by different methods for determining 
 moisture in flour. 
 
 Sample A (Fife) Sample B (Durum) 
 
 Method Method MethodMethodMethodMethod 
 
 A B C A B C 
 
 (Water (Vacuum) (Bas- (Water (Vac- (Bas- 
 Oven) set's) Oven) uum) set's) . 
 
 
 Percent 
 
 Percent PercentPercentPercentPercent 
 
 Leha Dunton, 
 
 
 
 
 Manhattan, Kan. 
 
 1 1. 01 
 
 11.90 
 
 11.55 io-52i 11-365 11-145 
 
 B. R. Jacobs, 
 
 
 
 
 Washington, D.C. 
 
 
 ^11.72 
 
 '11. 12 
 
 Agricultural 
 
 
 
 
 College, N. D. 
 
 10.13 
 
 
 10-07 9-54 9-65 
 
 R. F. Beard, 
 
 
 
 
 Agricultural 
 
 (10.32) ' 
 
 1 211.88 
 
 10.09 f (9.94 11.64)1 9.88 
 
 College, N. D. 
 
 .('10-91). 
 
 1 
 
 1(^10.91 2ii.47)|, ... 
 
 C. K. Glycart, 
 
 
 
 
 St. Paul, Mmn. 
 
 10.24 
 
 11.89 
 
 9-97 9-55 11-06 9.35 
 
 H. L. White, 
 
 
 
 
 Agricultural 
 
 (10.50) 
 
 10.56 
 
 10.595 (10.43)210.42 10.53 
 
 College, N. D. 
 
 (10.18) 
 
 
 ( 9-65) 
 
 G. A. Olson, 
 
 
 
 
 Pullman, Wash. 
 
 V-49 
 
 
 46.'?4 
 
 
 
 
 Averages 
 
 10.47 
 
 11.59 
 
 10.455 10-076 II. 18 10.109 
 
 I. 
 
 2. 
 
 3- 
 
 4- 
 
 "Drying in a vacuum \\/y. hours." 
 
 In vacuum oven at 70 C for periods ranging from 24 to 144 hours. 
 
 In aluminum dishes fitted with covers. 
 
 Kept in water oven at boiling temperature for 3 hours; not 
 
 included in average. 
 
 Miss Leila Dunton says: "Moisture Method A we do not use in 
 
 this laboratory for flour samples as it fails to remove all moisture. 
 
 Method B is very good. The vacuum desiccator we find very 
 
 convenient and accurate." 
 
WHEAT FLOUR 41 
 
 Associate Referee White says in his report to the Association: 
 "These results strengthen the conviction that for accurate results, 
 when working with materials that are affected by the temperature 
 of boiling water, the method utilizing the vacuum oven or desiccator 
 is the most accurate; but this method should be standardized as 
 regards temperature and other conditions. As indicated in the 
 footnotes to the preceding table, the time varied from 4^ hours to 
 144 hours, and the temperature from room temperature to 70° C." 
 
 "Method C (Bassett's) may well be considered further as a quick 
 method for the approximate determination of both moisture and fat." 
 
 It is to be noted that vacuum drying gave results about one per 
 cent higher (1.12) than drying in the water oven. All of these tests 
 show a low per cent of moisture. The flour was milled in the ex- 
 perimental mill of the North Dakota Experiment station. Sample 
 A, is designated a straight flour and sample B, a patent flour from 
 durum wheat. Tests reported show .70% (ash) for sample A and the 
 same for sample B (.697). If the flours were milled so as to show a 
 low moisture, the high ash could easily have resulted from lack of 
 proper tempering of the wheat before milling, as high ash results from 
 such a condition. 
 
 The Bassett method was one used extensively by the North 
 Dakota station in flour investigations in connection with weight 
 variations of flour during storage. This method, as is to be noted, 
 gives the same results as obtained by direct drying in the water 
 oven. 
 
 Omitting the extreme result, the five chemists using the vacuum 
 method of drying obtained results that differed by .58% (Sample B, 
 11.64 highj II .06 low.) One analyst however, Mr. H. J. White, the 
 Associate Referee, obtained from .76 to i.oi per cent below the 
 average by the vacuum method. This variation cannot be considered 
 as much the fault of the analyst as due to defects of the method. 
 In any series of flour moisture tests similar variations may occur. 
 
 29. Recent A. 0. A. C. Work on Flour Moisture. 
 
 For the past few years the Association has studied vacuum drying 
 without heat compared with vacuum oven drying at 70° C, and also 
 at 100° C with 20 to 28 inches of vacuum. The results fail to check. 
 For example one analyst from the Bureau of Chemistry reports 
 maximum moisture by drying in a vacuum desiccator over sulphuric 
 acid without heat for several days while another analyst of the 
 
42 WHEAT FLOUR 
 
 Bureau reports maximum results by drying in a vacuum oven at 
 ioo°C with 27 inches of vacuum. Then again, different desiccating 
 agents give different results. In some of the tests it is even reported 
 that the flour was dried in an 8 inch Hempel desiccator, containing 
 a litre of sulphuric acid. (J. O. A. A. C. Aug. 15, 1915, page 196) 
 
 In the case of sulphuric acid as a desiccating reagent, Associate 
 Referee Clarke mentions the necessity of avoiding the use of any 
 discolored sulphuric acid, and he gives the treatment necessary in 
 order to remove traces of organic matter from the acid. "Avoid the 
 use of discolored acid, as it frequently gives off some fumes of sul- 
 phur dioxide." J. O. A. A. C. Aug. 15, 1920 page 49. 
 
 You can start a test with c. p. sulphuric acid but when you apply 
 suction to the desiccator fine flour particles are liable to be drawn 
 from the dishes and be deposited in the acid causing it to give off 
 sulphur dioxide. 
 
 Sulphur dioxide, even in traces, has a marked action upon wheat 
 gluten proteins. When flour is fumigated with sulphur even lightly 
 as in case of fumigating for contagious diseases, such flour is rendered 
 practically valueless for bread making. Sulphur dioxide in mere 
 traces causes a catalytic action that splits the wheat protein molecules. 
 The fact that moisture results obtained by drying over sulphuric 
 acid in a vacuum desiccator are so erratic, sometimes more and 
 sometimes less than drying in the vacuum oven with extreme heat 
 and vacuum conditions, may be due to this catalytic action of sul- 
 phur dioxide, occurring in some but not all tests. Carefully con- 
 ducted microscopic tests show that such changes occur. 
 
 Proteins of most foods are not as sensitive to the action of sulphur 
 dioxide as wheat proteins, and because wheat proteins behave in 
 this way does not invalidate the use of vacuum desiccating drying 
 for foods in general. 
 
 In vacuum drying without heat, great care is necessary in the use 
 of the dehydrating agent. Flour is so exceeding fine it is easily 
 stirred, and too much shaking of the desiccator, as directed to mix 
 the acid, could easily raise a little flour dust that would be deposited 
 in the acid and make sulphur dioxide. 
 
 Associate Referee Clark's Report on Water in Foods and Feeding 
 Stuffs appearing in the Journal of the Association of Official Agri- 
 cultural Chemists Feb. 15, 1921, is particularly worthy of note and 
 the following quotations are from this report. 
 
WHEAT FLOUR 43 
 
 "In food control work a number of different procedures are 
 used for the determination of moisture or water, the method 
 employed depending on the nature of the material and equipment 
 of the laboratory. These methods can be classified as heating, 
 desiccator, refractometer, densimetric, or other procedures. The 
 temperature, pressure, type of apparatus, and other factors 
 differ in each class. It is not surprising, therefore, that the 
 determination of water is quite variable and that it is next to 
 impossible for two laboratories to obtain good checks. 
 
 "As ordinarily determined, the water or moisture in food products 
 is derived from several sources, the principal ones being loosely 
 bound moisture, water of constitution, and water derived from 
 the decomposition of organic materials. If the moisture is 
 determined by difference, low boiling and gaseous substances 
 other than water will be lost. In the process of drying, other 
 changes, more or less pronounced, always take place. Certain 
 constituents may be oxidized, as in linseed meal, or other sub- 
 stances containing a drying oil. Many feed materials lose weight 
 on heating until a certain minimum weight is obtained, when 
 they begin to increase in weight. 
 
 "As ordinarily used, the term 'per cent of moisture,' or 'per 
 cent of water' in a food material is intended to mean the loosely 
 bound water in the material, or, in substances in which the 
 water occurs as a solvent, sirups, etc., the actual uncombined 
 water present. It is not possible in ordinary work to determine 
 this water without including water from other sources or other 
 volatile materials. For the purpose of this association a few 
 well-selected methods are needed which will give a consistent 
 measure of the moisture in such substances as feed materials, 
 and a measure of the actual water in such substances as sirup. 
 Such selected methods should give comparative results when 
 used with care with the equipment found in the ordinary lab- 
 oratory. 
 
 "It is quite possible that the treatment in vacuo at the tenipera- 
 ture of boiling water is too strenuous to remove the moisture 
 from some materials without other changes being too pronounced. 
 It may be a better procedure to dry such material at a lower 
 temperature in vacuo. The statement 'in a current of dry 
 hydrogen or in vacuo' is extremely vague, and it is not probable 
 that concordant results could be obtained if these instructions 
 were followed. The simple specification 'in vacuo' may mean 
 less than i mm., or 70 mm. or absolute pressure." Page 344. 
 
 Last year (1921) the A. O. A. C. decided (2) "That work on the 
 determination of moisture and ash be discontinued until further re- 
 search develop more desirable methods." (J.A.O.A.C. Vol. VI No. 2) 
 
44 WHEAT FLOUR 
 
 JO. Results of Later Comparative Moisture Tests. 
 
 Mr. L. E. Leatherock reports a series of co-operative tests conducted 
 by 69 chemists all reporting on the same sealed sample of flour sent 
 out for the purpose of testing methods employed in different labora- 
 tories. (See July 1922 Journal of the American Association of Cereal 
 Chemists, pages 102-107.) 
 
 59 laboratories used air ovens for drying the flour at about 103° 
 to 105° C for periods ranging from 4 to 8 hours. General average 
 moisture 14.15 per cent. 
 
 10 laboratories used vacuum ovens, with temperatures ranging 
 from 95 to I40°C with time limits from 5 minutes to 5 hours, and 
 vacuum employed not reported. General average moisture 14.45 
 per cent, ranging from 14. 1 to 14.74. 
 
 No tests are reported with water oven drying. Had such tests 
 been made they would have shown appreciably lower results than 
 air drying at 103-5, presumably .6 per cent. 
 
 "About the only definite conclusion we are able to draw from 
 all this data was the fact that we did not know how much moist- 
 ure the flour contained, and that the layman unfamiliar with 
 laboratory work would be fully justified in wondering why more 
 concordant results were not obtained on check samples that 
 are now frequently sent around in so-called air-tight containers." 
 
 Among the conclusions drawn are: "Laboratories using air ovens 
 and vacuum ovens cannot check between one another; vacuum 
 oven gives higher results." The necessity for standardizing time 
 and temperature, and the limitation of the range of temperature for 
 air ovens is noted. 
 
 Mr. Leatherock's report is of particular interest as it shows that 
 in commercial practice over 85% of the laboratories that do regular 
 flour testing use air drying, and 15 per cent use vacuum oven drying. 
 
 Vacuum drying does not represent present day trade conditions. 
 The expense of installing a vacuum oven in many laboratories 
 would be prohibitive. The statement made by the Bureau of 
 Chemistry in 1902 that "the drying of samples in vacuo was not 
 considered practicable as few laboratories are equipped to use this 
 method, and the large bulk of work also prohibits it," is particularly 
 applicable to flour mill control work today. 
 
 J/. Moisture Content of Flours Determined by Different Methods. 
 
 Shutt and Moloney in Trans, of the R. Sc. of Can., 1917, give some 
 interesting facts on this point. 
 
WHEAT FLOUR 45 
 
 They first tested drying flour in dry hydrogen, and then in vacuum 
 at ioo° C, 291^ inches vacuum. The vacuum drying gave a suggestion 
 higher results — ranging from .05 to .11 per cent, subsequent drying 
 in air following hydrogen drying gave no change. The following 
 table presents results obtained in various ways of drying: 
 
 Comparison of results from vacuum oven drying with those from 
 electric air oven at ioo°C and at iio°C., and water oven at 91° C. 
 
 Series Oven Tem- Time Percentage of moisture 
 perature abed 
 
 A..,. 
 
 . . . Vacuum 
 Vacuum 
 
 ioo°C 
 ioo°C 
 
 5 
 + 5 
 
 12.63 
 
 12.79 
 
 12.64 
 
 12.77 
 
 12.60 
 
 12.77 
 
 
 B... 
 
 . . . Vacuum 
 El. air 
 Vacuum 
 
 ioo°C 
 ioo°C 
 ioo°C 
 
 5 
 + 16 
 
 + 5 
 
 12.52 
 11.42 
 12.57 
 
 12.55 
 11.57 
 12.58 
 
 12.53 
 11.67 
 12.64 
 
 
 C... 
 
 . . . Vacuum 
 El. Air 
 Vacuum 
 
 ioo°C 
 iio°C 
 
 ioo°C 
 
 S 
 + 17 
 + 5 
 
 12.44 
 12.25 
 12.55 
 
 12.42 
 12.26 
 12.59 
 
 12.43 
 12.26 
 12.59 
 
 12.46 
 12.29 
 12.60 
 
 D Vacuum ioo°C 5 13.43 i3-4i 
 
 Water 9i°C +18 11.92 11.97 
 Oven 
 
 Vacuum ioo°C +5 13.42 13.38 
 
 Four series of tests were made. A, B, C and D, and triplicate 
 samples a, b, c, d, tested in each series. For series A, it is noted 
 under time, 5 hours, that the moisture results for vacuum drying 
 are 12.63 12.64, 12.60. Then these same samples were dried 5 
 hours longer", and 12.79, 12.77 and 12.77% moisture was secured, a 
 gain of .15% resulting from five hours additional drying. In series 
 B, samples were first dried 5 hours in the vacuum oven at ioo°C, 
 then these same samples were dried 16 hours additional in an air 
 oven at 100° C, and then dried again five hours in the vacuum oven. 
 It is to be noted that the air drying showed less moisture but that 
 .15 more moisture was obtained after five hours additional vacuum 
 drying. The drying at 110° C air maintained the weights more 
 closely with vacuum drying than any other method. Water oven 
 drying gave about 1.50 less moisture than vacuum drying and air 
 oven at 100° C about one per cent less than vacuum drying. 
 
 An examination of Shutt and Moloney's results show that with 
 
46 WHEAT FLOUR 
 
 the vacuum drying prolonged beyond five hours, there was a general 
 tendency for higher moisture results. This additional loss could 
 have come from mechanical losses caused by the suction of the air 
 pump removing fine flour particles. As high as .17% mechanical 
 losses may have occurred during each 5 hours' vacuum drying. 
 J2. Standards of Purity for Food Products. 
 
 The Food and Drugs Act makes no provision for Food Standards. 
 The Secretary of Agriculture, in 1920 reported. (Page 60) 
 
 "In order to secure the more effective and efficient enforcement 
 of the food and drugs act, the department should be specifically 
 authorized to establish standards of strength, quality and purity 
 for the articles subject to its provisions, and ample power should 
 be given it to enforce compliance with the standards." While the 
 standards do not have the force of law, nevertheless reasonable 
 standards, founded upon the best trade practices, are alike helpful 
 in the enforcement of the Food and Drugs Act and in commercial 
 transactions. 
 
 In the appropriation act for the Department of Agriculture, 1902, 
 Congress authorized the Secretary of Agriculture to make certain 
 investigations relative to foods, and among the specifications are: "To 
 enable the Secretary of Agriculture, in collaboration with the Associ- 
 ation of Official Agricultural Chemists, and such other experts as 
 he may deem necessary, to establish standards of purity for food 
 products, and to determine what are regarded as adulterations 
 therein, for the guidance of the officials of the various states and of 
 the courts of justice." 
 
 One set of standards — Circular No. 10 — was issued under this act. 
 No standards for flour or grain products are included in this set of 
 standards proclaimed November 20, 1903. 
 
 The following session of Congress passed the same act but ending 
 with the words: "adulteration therein." The appropriations act 
 for 1903-1905 did not carry the clause reading: "for the guidance 
 of officials of the various states and ot the courts of justice." Hence 
 the Standards Committee in their work, conducted under the later 
 appropriations act, 1903-1905, did not formulate standards for the 
 guidance of officials and courts. W^hen the Standards Committee 
 submitted its report containing the definition of flour and the 13^ 
 per cent moisture standard to Secretary Wilson, December 19, 1904, 
 the Committee supposed they were working under the act giving 
 authority for formulation of standards for the guidance of officials 
 
WHEAT FLOUR 47 
 
 and courts. (See page 10 Bureau of Chemistry Bulletin 69 Re- 
 vised part I.) Circular 19, issued later, superseded the standards 
 of December, 1904, circulars 13 and 17, and also circular 10 which 
 is the only standard formulated and published for the guidance 
 of officials and courts. Circular 136, Standards of Purity for Food 
 Products, suspends circulars 13, 17 and 19, but does not mention 
 circular 10. It is generally supposed that all the standards formu- 
 lated by the Standards Committee in its early work, prior to the Food 
 and Drugs Act, was "for the guidance of officials and courts," but the 
 acts of Congress show that this is not the case. 
 
 33- The Moisture Standard Should not be Changed by Changing the 
 Method of Determining Moisture. 
 
 The 133^ per cent moisture standard should have a definite and 
 fixed meaning. It should mean the same today as when first pro- 
 mulgated and as understood by the millers at the 1915 Hearing. 
 Three courses are open for accomplishing this: 
 
 I. Continue the open air moisture drying methods with time and 
 temperature limits as in former A. O. A. C. methods for foods and 
 as is now official for sugar, milk, butter, cheese and many agricul- 
 tural products; 
 
 1. Use "vacuo" drying with heat, specifying the time, tempera- 
 ture and vacuum and allowing for the fine flour removed during 
 the drying process. This would necessitate a moisture standard 
 of i4>^ per cent or more and would include water of hydration. 
 About fourteen and one half per cent moisture under such conditions 
 corresponds with the standard formulated in 1904; 
 
 3. Adopt a definition for flour without reference to moisture con- 
 tent and then the U. S. Department of Agriculture issue a service and 
 regulatory announcement fixing 13^^ per cent moisture, water oven 
 basis or i^}^ per cent, vacuum oven basis, as the maximum allow- 
 able for adjusting the weight of flour packages. 
 
 The introduction and development of moisture methods that give 
 one or more per cent moisture than was obtained by the methods 
 used for securing the data upon which the standard was formulated 
 simply reduce the moisture standard for flour one per cent or more. 
 
 This unintentional changing of the standard seriously affects flour 
 milling operations and the transportation, sale and legal status of 
 flour. The whole matter should receive careful consideration and 
 proper adjustment. 
 
48 WHEAT FLOUR 
 
 Regulation 4, Food and Drugs Act specifies that the methods of 
 the A. O. A. C. shall be used as official methods in testing food, 
 provided, however, that any method satisfactory to the Bureau of 
 Chemistry may be employed. Under the provisions of this regulation 
 the Bureau of Chemistry and then the Department of Agriculture 
 must act when methods of analysis and standards fail to harmonize 
 and fail to reflect the best trade practices. 
 
 It is not surprising as methods of analysis change, that they 
 affect old standards founded upon former methods, and that con- 
 ditions such as exist in relation to the method for determining moisture 
 in flour and the moisture standard should occur. The wonder is that 
 more such anomalous conditions do not occur. 
 
 34. The Relation of the Standard to the Food and Drugs Act. 
 
 A moisture standard for flour, it would seem, should harmonize 
 with the Food and Drugs Act and the Authorized Regulations. As 
 the present standard was formulated two years prior to the advent 
 of the act, the Standards Committee could not anticipate the law, 
 the standard, however, can be interpreted to harmonize with 
 the law. A moisture standard cannot consistently maintain that 
 a sound flour at no time and under no conditions, (that is, without 
 regard to any other factor) shall not exceed 13^^ per cent moisture. 
 We know that flour milled with less than 135^ per cent moisture 
 will, under natural conditions absorb more than 133^2 per cent, and 
 still be sound. The Food and Drugs Act and Regulation 26 take into 
 account such natural weight deviations due to either absorption or 
 evaporation of moisture. No standard should attempt to limit 
 what the law and regulations permit. Furthermore, hygroscopicity 
 follows nature's laws. The water added by nature cannot be regarded 
 as water added by the miller. Provided the flour contains its full 
 original dry matter, loss or gain of moisture in no way aflfects the 
 consumer. To require the drying of flours that are sound and origin- 
 ally packed full weight without excess moisture, benefits no one 
 except, perhaps those who want to dry the flour or the persons who 
 want to breach a contract. Drying may result in injury, as flour 
 is easily affected by heat. A standard should not be invoked to do 
 unreasonable or unnecessary acts which are not in harmony with 
 the law, authorized regulations, or good commercial practice. 
 
 35. Moisture Absorbed or Lost During Manufacture. 
 
 There is another phase of this question that must be taken into 
 
WHEAT FLOUR 49 
 
 consideration in handling flour. A manufacturing tolerance is 
 necessary to cover variations in weight due to changes in humidity 
 of the atmosphere while the flour is being manufactured and packed. 
 The original Regulation No. 29, Statement of Weight or Measure, 
 suggests such a tolerance. It reads: 
 
 "(b) A reasonable variation from the stated weight for indi- 
 vidual packages is permissible, provided this variation is as 
 often above as below the weight or volume stated. This vari- 
 ation shall be determined by the inspector from the changes in 
 humidity of the atmosphere from the exposure of the package 
 to evaporation or to absorption of water and the reasonable 
 variations which attend the filling and weighing or measuring of a 
 package." 
 
 The influence of humidity upon the moisture content and weight 
 of flour during milling has been studied by the U. S. Department 
 of Agriculture. See Bulletin No. 1013. Humidity conditions in the 
 mill often change suddenly and cannot be foretold by the miller, as 
 normal humidity conditions cannot be uniformly maintained in a 
 flour mill. 
 
 In the bulletin cited it is stated that when hard wheats of various 
 moisture contents were tempered to the same moisture basis of 15 
 per cent and were milled under different humidity conditions: 
 
 "No very pronounced relation between the moisture content 
 of the flour and that of the wheat before tempering was shown, 
 or in other words, no relation was shown of moisture content 
 of flour to the quantity of temper water added to the wheat. 
 On the other hand, a decided tendency was shown for the moist- 
 ure content of the flour to increase as the relative humidity 
 increased, a difference of 10 per cent in relative humidity making 
 an average difference of approximately one half of one per cent 
 in the moisture content of the flour." 
 
 These changes in the humidity affecting the moisture of the flour 
 as determined by the U. S. Department of Agriculture, are reasonable 
 variations which attended the manufacture of flour and the filling 
 and weighing of flour packages. It is believed that such weight 
 variations should constitute a tolerance occurring in milling and 
 packing conducted in compliance with good commercial practices. 
 Regulation No. 26 does not appear to either exclude or include 
 such a tolerance. It is an uncontrollable variation that occurs 
 and affects the weight as often in one direction as it does in another. 
 
50 WHEAT FLOUR 
 
 The operative miller must have a margin to cover such moisture 
 changes occuring in milling operations. The best trade practice 
 should ultimately be taken as a guide and the U. S. Department 
 bulletin cited is comparable with the best trade practices as to in- 
 fluences of humidity changes in flour milling. 
 
 j(5. Packing and Weighing Flour to Comply with Food and Drugs 
 Act. 
 
 Flour packers are generally experienced and high grade men, and 
 would resent a suggestion of short weighing on the part of 
 an employer; and a miller could not deliberately short weigh his 
 flour without the knowledge of the packer. The weigh masters of 
 most states and cities frequently inspect the miller's scales. The 
 railroads and transportation companies also check the mill weights. 
 If the miller did not deliver accurate weights his books would not 
 balance, the miller's bankers would know it and in turn would refuse 
 to give him credit. Errors may arise in filling and weighing packages 
 but actual intentional short weighing of flour is of unusual occur- 
 rence. When-it does occur it is inexcusable. 
 
 Some means of weighing and inspection should be developed 
 whereby the miller, the inspector, and the flour dealer can alike 
 unite upon a system that will secure reasonable accuracy. High 
 grade flour packers, might be appointed accredited weighmasters 
 after complying with certain state or national requirements. The 
 miller should have some way whereby he can pack his products, 
 have them inspected and passed and not be placed in the embarrass- 
 ing position of being libeled because of uncontrollable atmospheric 
 conditions. 
 
 The purchaser is entitled to flour packed full weight without excess 
 of moisture. To determine if this has been done, full consideration 
 must be given to all the factors mentioned in section 7 and discussed 
 in sections 8 to 12. The great difficulty is lack of appreciation of 
 the extent to which flour, packed so as to fully comply with the Food 
 and Drugs Act, may subsequently vary in weight and moisture 
 content while the dry matter weight remains practically unchanged 
 and the value of the flour is unimpaired. 
 
 3J. Principles Involved in Determining Flour Moisture and Weight 
 as Indorsed by Trade Organizations. 
 
 A committee consisting of members from the Millers National 
 
WHEAT FLOUR 51 
 
 Federation, The Association of Operative Millers, and the American 
 Association of Cereal Chemists, known as the Allied Associations' 
 Committee has considered this question of weight and moisture 
 content of flour. They recommended that only the "free moisture" 
 of flour be recognized as moisture and not other forms, or mechanical 
 losses due to aspiration; and also that weight regulations be based 
 on not to exceed ^3}4 per cent moisture as determined by the methods 
 used in formulating the standard. 
 
 These resolutions provide for the continuance of the i^yi per cent 
 moisture standard on its original basis, and emphasize that a mois- 
 ture standard rests upon the method used for the determination of 
 the moisture. One should not be changed without a corresponding 
 change of the other. 
 
 j8. Adjustment. 
 
 This whole question of the weight and moisture content of both 
 wheat and flour and their maintenance on a parity basis rests upon 
 a few fundamental facts as stated. A common method for deter- 
 mining moisture in each has been used, and a wheat standard and 
 a flour standard have alike been formulated on that basis (water 
 oven drying). The grain moisture method is provided for in the 
 Grain Standardization Act, and the Secretary of Agriculture is 
 authorized to establish the method. He is also chief executive 
 officer of the Food and Drugs Act, and it would seem that he is the 
 one to determine whether the moisture method for wheat and flour 
 shall remain on a parity and the I3>^ per cent flour moisture standard 
 be continued as originally proclaimed, or whether by the use of 
 another and different method for determining moisture in flour, the 
 parity between wheat and flour shall be changed and the present 
 flour moisture standard lowered. 
 
 Jp. Economic Features Involved. 
 
 There are certain industrial and economic features involved in a 
 flour moisture standard that need to be noted. Dr. Alonzo Taylor in 
 "War Bread," page 76 says: "In comparing American and European 
 extractions, the water content of flours must be kept in mind. Here 
 the flour contains about 13 per cent of water, in Europe higher 
 water content is permitted, 17 per cent being common." American 
 flour must compete with European flour. European governments 
 without exception encourage the importation of wheat so their own 
 
52 WHEAT FLOUR 
 
 millers can manufacture flour. European governments all want 
 to import raw material, as wheat, and make manufactured 
 products, and hence try to avoid importing any flour. The 
 American Miller does not want a high moisture standard. He 
 has advocated just as low a standard as he can consistently operate 
 under, 12}4 per cent. But to change the method of determining 
 the moisture so as to lower the standard to 12^ per cent, places him 
 in a position that he cannot successfully mill flour and compete in 
 the world's markets. To attempt to operate on a 12^ per cent 
 standard would raise the price of flour and also result in still further 
 curtailment of export flour trade. Furthermore, if the manufacture of 
 flour is curtailed by standards, and the domestic demand for wheat 
 is lessened the farm price of wheat drops correspondingly. 
 
 If an agitation is started in this country to the effect that the Amer- 
 ican Miller is adulterating his flour with water some foreign govern- 
 ment may have a pretense of an excuse for excluding American flour, 
 which treaty rights now prevent. Some years ago an European 
 country tried to exclude American flour claiming it was adulterated 
 with copper sulphate, and it took time and costly effort to disprove 
 the libel. 
 
 During present reconstruction times it would be most unfortunate 
 to suggest that the American Miller adulterates his flour with water, 
 unless the facts actually warranted such statements, because it would 
 be another factor tending to create unrest and distrust. 
 
 Export and domestic flour business are done on narrow margins 
 and to change an established weight standard one per cent, by chang- 
 ing a moisture method, would be a deciding factor as to whether 
 a mill be operating or idle. And when flour mills are not operating 
 the demand for wheat lessens and the price drops. I do not believe 
 that any one desirous of broadening American markets, would 
 knowingly take a step that would unquestionably lower the farm 
 price of wheat. The world's commercial relations are so delicately 
 poised today that it takes but little to disturb trade conditions. 
 
 The American Miller justly feels proud of his product and has 
 never countenanced adulteration in any form. Washington at his 
 mill in Mount Vernon set a very high standard, his flour being ac- 
 cepted in many of the markets of the world without inspection. 
 Later Abraham Lincoln honored the craft as a grist mill hand and 
 was known as "Honest Abe". Long before the Food and Drugs 
 Act the millers were instrumental in having a special law passed 
 
WHEAT FLOUR 53 
 
 preventing the adulteration of flour — the mixed flour law, which 
 safeguards the purity of flour more effectually than the Food and 
 Drugs Act. Various attempts have been made to repeal the mixed 
 flour law, but so far these attempts have been unsuccessful. During 
 the world war when the question of bread supply was so acute and 
 promised to be one of the features that meant success to the Allied 
 Army, it was the American millers under the guidance of Herbert 
 Hoover that developed and put into execution the plans for making 
 and distributing flour. They discharged this trust in a most honor- 
 able way. The Millers National Federation and other trade organ- 
 izations representing the best trade practices have made their 
 recommendations as to the basic principles that are involved in 
 this question of the moisture content and weight of flour, and these 
 recommendations are in harmony with the Food and Drugs Act, 
 the Authorized Regulations and the best trade practices. 
 
INDEX TO TOPICS DISCUSSED 
 
 (Numbers Refer to Paragraph Sections.) 
 
 1. Hygroscopicity of flour, and its effect upon weight. 
 
 2. Water as a component of wheat and flour. 
 
 3. The tempering of wheat is a recognized necessity and a long 
 estabhshed feature of milling. 
 
 4. Moisture content of flour milled under good commercial con- 
 ditions. 
 
 5. Weight and moisture content of flour are inseparable attributes. 
 
 6. The dry matter content of flour. 
 
 7. Factors affecting the dry matter content of flour. 
 
 8. Allowable tolerences in weighing packages. 
 
 9. Drawing flour samples for moisture tests. 
 
 10. Accuracy of present methods for determining moisture in flour. 
 
 11. Calculating dry matter content from weight and moisture per- 
 centages does not give original dry matter weight as packed 
 when mechanical losses occur. 
 
 12. Calculated dry matter content of flours after storage and 
 transportation compared with dry matter content of flours 
 when packed. 
 
 13. When flour is packed full weight and without excess moisture, 
 does it not comply with the Food and Drugs Act, so long as the 
 flour remains sound and wholesome and is in its original con- 
 tainer? 
 
 14. What was the prevailing method or methods in use at the time 
 of the Hearing of the flour moisture question at Washington in 
 
 15. The methods for determining moisture in wheat and flour should 
 remain on a parity. 
 
 16. The American Association of Cereal Chemists' Method for 
 Moisture. 
 
 17. The present ofiicial vacuum oven method for the determination 
 of moisture in flour is not accurate. 
 
 18. Water of Hydration of Wheat Proteins. 
 
 19. Mechanical losses in vacuum drying. 
 
 20. The 12}4 per cent moisture standard for flour is based on the 
 Water Oven Drying Method. 
 
 21. Vacuum drying of foods at ioo°C never officially adopted. 
 
 22. Drying in vacuum without heat. 
 
 23. Extent to which flours range in moisture content. 
 
 24. Flours with 15 per cent moisture not considered spoilage. 
 
 25. Moisture content of foreign flours. 
 
 26. Official methods for moisture not followed in official laboratories. 
 
 54 
 
INDEX TO TOPICS DISCUSSED 55 
 
 27. No short weighing or excess moisture of flour is to be entertained. 
 
 28. Results of first co-operative A. O. A. C. tests of drying flour in 
 vacuum oven and in water oven. 
 
 29. Recent A. O. A. C. work on methods for determining moisture 
 in foods. 
 
 30. Results of later comparative moisture tests. 
 
 31. Moisture content of flour determined by different methods. 
 
 32. Standards of purity of food products. 
 
 23. The Moisture Standard should not be changed by changing the 
 method of determining moisture. 
 
 34. Relation of the standard to the Food and Drugs Act. 
 
 35. Moisture absorbed or lost during filling of packages. 
 
 36. Packing and weighing flour to comply with the Food and Drugs 
 Act. 
 
 37. Principles involved in determining flour moisture and weight 
 as indorsed by Trade Organizations. 
 
 38. Adjustment. 
 
 39. Economic features involved