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LIBRARY OF THE 
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 OF HOME ECONOMICS 
 
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Cornell University 
 Library 
 
 The original of tiiis book is in 
 tine Cornell University Library. 
 
 There are no known copyright restrictions in 
 the United States on the use of the text. 
 
 http://www.archive.org/details/cu31924003581638 
 
U. S. DEPARTMENT OF AGRICULTURE. 
 
 FARMERS' BULLETIN No. 112, 
 
 BREAD 
 
 THE PRINCIPLES OF BREAD MAKING. 
 
 HELEN W. ATWATER. 
 
 PREPARED UNDER THE SUPERVISION OF THE OFFICE OF EXPERIMENT STATIONS. 
 A. C. TRUE, Director. 
 
 WASHINGTON: 
 
 GOVERNMENT PRINTING OFFICE. 
 1900. 
 
LIBRARY OF THE 
 NEW YORK STATE COLLEGE 
 OF HOME ECONOMICS 
 
 CORNELL UNIVERSITY 
 ITHACA, NEW YORK 
 
LETFER OF TRANSMITTAL. 
 
 U. S. Department of Agriculture, 
 
 Office of Experiment Stations, 
 
 Washington, D. G. , Jcmuxi/ry W, 1900. 
 Sir: I have the honor to transmit herewith an article on bread and 
 the principles of bread making, prepared by Miss Helen W. Atwater, 
 in accordance with instructions given by the Director of this Office. 
 In preparing this bulletin Miss Atwater has consulted the available 
 sources of information, including standard works on the subject, and 
 has prepared the material for publication under the supervision of 
 Director C. D. Woods, of the Maine Agricultural Experiment Station, 
 who for some time has been immediately concerned with the investi- 
 gations conducted under the auspices of this Office which have had to 
 do with bread and bread making. 
 
 Perhaps no topic connected with the subject of human food is of 
 more general interest than bread, and this bulletin, which summarizes 
 the most recent information on the subject, is believed to be useful and 
 timely, and its publication as a Farmers' Bulletin is, therefore, respect- 
 fully recommended. 
 
 Respectfully, A. C. True, 
 
 Director: 
 Hon. James Wilson, 
 
 Secretwry of Agriaultn/re. 
 
CONTENTS. 
 
 Page. 
 
 Introduction 7 
 
 Grains and flours 8 
 
 Wheat 9 
 
 Structure 9 
 
 Composition 9 
 
 Milling 11 
 
 Impurities and falsifications of wheat flour 13 
 
 Rye .._ 13 
 
 Barley and oats 14 
 
 Corn, or maize 14 
 
 Rice, millet, buckwheat, etc 15 
 
 Yeast and other leavening agencies 15 
 
 The theory of fermentation 15 
 
 Yeast 17 
 
 Substitutes for yeast 18 
 
 Raised bread 19 
 
 Preparation of the dough 20 
 
 Straight dough 21 
 
 Sponge dough 21 
 
 Ferment, sponge, and dough method 22 
 
 Scotch barm method 22 
 
 Bread made with leaven 23 
 
 Special breads 24 
 
 Fancy leavened breads 24 
 
 Unleavened breads 24 
 
 Household methods of bread making 25 
 
 Quick-raising method 25 
 
 Slow-raising method 26 
 
 Baking and cooling 26 
 
 Chemical composition 28 
 
 Stale bread 29 
 
 Imperfections and impurities in bread 30 
 
 Nutritive value and cost of bread 32 
 
 Comparison of the composition of breads and other foods 32 
 
 Digestibility of different kinds of bread 33 
 
 Market value of bread 36 
 
 Summary 37 
 
 5 
 
ILLUSTRATIONS. 
 
 Page. 
 
 Fig. 1. — Section of grain of wheat 9 
 
 2. — Section of grain of corn 14 
 
 3. — Yeast plant 17 
 
 6 
 
BREAD AND THE PRINCIPLES OF BREAD 
 
 MAKING. 
 
 INTRODUCTION. 
 
 There is hardly any food, except milk, which is so universally used 
 as bread; and not only is it now known almost everywhere, but since 
 history first began it has in some form or other made one of the 
 staples of diet among all but the most savage peoples. In the earliest 
 historical records it is spoken of, and the wild tribes which to-day 
 inhabit South Africa know something of its use. Of course the bread 
 made by the Kafir to-day, or by the American Indian three hundred 
 years ago, is very different from our own. It would be interesting to 
 trace the relationship between the bread-making processes of given 
 peoples and their rank in the scale of civilization. The Kafir simply 
 grinds his grain between two stones, makes a paste of this meal and 
 water, and bakes it in the ashes of his camp fire; Israel, in Egypt, ate 
 leavened bread; the ancient Greeks cultivated the yeast plant; in 
 Pompeii an oven was found containing eighty -one loaves of bread not 
 unlike our own; the Swiss peasant still bakes his weekly loaves in the 
 village oven; and so on, to the mammoth bakeries and innumerable 
 fancy breads of our own large towns. Such a classification would 
 not be utterly absurd, for except among the lowest savages and in the 
 extremest climates some kind of grain is recognized as a necessary 
 food, and bread furnishes it in one of its most convenient forms — that 
 is, a form in which it yields the greatest amount of nourishment for 
 the least labor and cost. No wonder, then, that the more intelligent 
 a people the better bread they make. 
 
 The reason for this importance of bread is very simple. Ever since 
 the far-off days when our forefathers first found the wild cereals, or 
 began to cultivate them, men have known that food prepared from 
 them would support life and strength better than any other single 
 food except milk. The diet of the poor in India and China often 
 consists almost entirely of wheat or millet cakes or rice, and although 
 in our own land the ease with which we can get other foods makes 
 bread seem less important, there are still many districts in Europe 
 where the people eat very little else. To a large part of mankind it 
 
 7 
 
8 
 
 is still the staff of life, and if the}' pray for their daily bread they 
 mean it literally. 
 
 In regard to its ingredients, bread is one of the simplest of our cooked 
 foods, but in regard to the changes which the raw materials must 
 undergo to produce a finished loaf, it is one of the most complicated. 
 Flour, water, a pinch of salt, and a little yeast — the necessary things 
 can be counted on the fingers of one hand, yet one of the few books 
 which describes the processes of bread making with any degree of com- 
 pleteness is a large volume of over 600 pages. It is the purpose of this 
 bulletin to give a brief account of these processes — to describe the raw 
 materials from which the bread is made, and the changes which they 
 undergo in the preparation and baking of the dough, with the signifi- 
 cance of each to the quality of the bread and its value as food. But 
 before going into a detailed description of these processes it will, 
 perhaps, be well to recall what the main steps in bread making are. 
 
 Beginning back in the flour mill, the grain is ground into powder, the 
 coarser parts of which are sifted out as bran, while the finer constitute 
 our flour. Once in the baker's hands, the flour is mixed with water and 
 yeast, or something which will produce the same effect. When this 
 paste or dough, containing yeast, is set in a warm place the yeast begins' 
 to "work," as we say, and the dough to "rise;" in other words, the 
 yeast causes a change known as alcoholic fermentation to set in, one of 
 the principal results of which is the production of carbon dioxid gas. 
 If the dough was well mixed, this gas appears all through it, and, 
 expanding, leavens or raises it. After the yeast has worked sufficiently 
 the dough is shut up in a hot oven. Here the heat kills the yeast and 
 prevents further alcoholic fermentation, causes the gas to expand and 
 stretch open the little pockets which it forms between the particles of 
 dough, and changes some of the water present into steam, thus raising 
 the loaf still more. Further, the heat "hardens and darkens the outer 
 layers into what we call the crust. The sum of these changes in the 
 oven we call baking. When they have been continued long enough our 
 bread is "done," ready to cool and eat. 
 
 GRAINS AND FLOURS. 
 
 Flours, as everyone knows, are made by grinding the grains of the 
 various cereals, wheat, rye, barley, oats, maize, millet, rice, etc. Of 
 these, wheat is the most important partly because it can be cultivated 
 in any temperate climate, but chiefly because it yields the flour best 
 suited to bread making, the aim of which is to produce the most appe- 
 tizing and nutritious loaf at the least expense. While the various 
 cereals differ largely in their chemical composition, most of them are 
 very similar in the structure of their grains, so that if we study the 
 
formation and milling of wheat, we can easily understand the produc- 
 tion of flour from the others. 
 
 WHEAT. 
 
 structure. — The wheat grain (fig. 1) is a small oval seed, which can be 
 easily thrashed from the stalk on which it grows. Its six outer layers 
 are known to the miller as the bran. Of these, the three outermost 
 form what is called the skin of the grain 
 and constitute 3 per cent, by weight, of 
 the entire seed. The three remaining 
 layers of the bran form the envelope of 
 the seed proper. The outer one is known 
 as the "testa," and contains the greater 
 part of the coloring matter of the bran. 
 Inside it lies a thin layer of membrane. 
 These two together form 2 per cent, by 
 weight, of the entire grain. The inner- 
 most layer of the bran, called the cereal 
 or aleurone layer, is made up of rectan- 
 gular cells, filled with a nitrogenous 
 substance known as cerealin or aleurone. 
 Its weight is about 8 per cent of that of 
 the entire grain, making the total weight 
 of the bran about 13 per cent. In mill- 
 ing it is exceedingly difficult to separate Pig. l.-Section of grain of wheat: a, sWns 
 these three inner layers of the bran. and testa; 6, membrane ; e, embryo ; d, 
 1 . 1 T 1 1. endosperm; e, cereal or aleurone layer;/, 
 
 Within the cerealin layer lies the endo- scuteiium. . 
 sperm, as the portion of the grain adjacent to the embryo is called, 
 which constitutes the larger part of the grain and consists of irregular 
 shaped cells containing starch granules. At the lower end of the grain, 
 almost surrounded by the endosperm, lies the germ or embryo. A 
 portion of the embryo is called the scuteiium. This serves a special 
 purpose in germination. When the grain has thoroughly ripened and 
 has been placed in favorable conditions, this embryo will develop into 
 a new plant; as it begins to grow it will feed upon the starch and other 
 substances in the endosperm. 
 
 Composition. — The five outer layers of the bran contain very little 
 except cellulose, a woody, fibrous substance forming the cell walls. 
 When burned, the ash of bran is found to contain a fairly large pro- 
 portion of phosphoric acid, potash, and small amounts of other mineral 
 matters. The cereal layer is, of all parts of the grain, the richest in 
 nitrogenous substances, the chief of which is the cerealin from which it 
 takes its name. The endosperm contains, besides the cellulose of its 
 cell walls, large quantities of starch, a little sugar, and a nitrogenous 
 substance known as gluten. The germ contains cellulose, nitrogenous 
 
10 
 
 substances, sugar, and a very large proportion — 9 to 12 per cent — 
 of fat. 
 
 Grain, being hygroscopic — that is, having the power of absorbing 
 water from the atmosphere — varies with the weather in the amount of 
 moisture which it contains; similarly, wheat grown in a wet season or 
 a humid climate holds a larger percentage of moisture than the same 
 kind grown under drier conditions. Thus English wheat contains 3 or 
 4 per cent more water than American. From comparison of many 
 analyses, the average weight of the water in the grain is found to be 
 about 12 or 13 per cent of its total weight. 
 
 Different kinds of wheat also vary as to the amount and quality of 
 gluten which they contain. As gluten is one of the most impor- 
 tant constituents of the wheat, the baker should know the character of 
 the gluten in the flour he uses. The so-called "hard" wheats are rich 
 in gluten of a strong, tenacious character, while " soft " wheats contain 
 less gluten and proportionately more starch. The gluten of hard wheat 
 can be mixed with large amounts of water, and produces a large loaf 
 from a comparatively small quantity of flour. Soft wheat, on the 
 other hand, while it does not yield so large a loaf, makes a bread con- 
 taining less water, and having a milder and more agreeable flavor. 
 
 It is useful for those interested in milling to know what parts of 
 the grain will be most valuable in yielding a nutritious flour capable 
 of making a' white, well-raised loaf. In considering the nutritive 
 value of flour let us remember the principal kinds of nutrients which 
 the body needs: (1) The nitrogenous substances, called protein com- 
 pounds or proteids, typified by the white of egg and the lean of meat, 
 and chiefly represented in wheat by the cerealin and the gluten — these 
 are the tissue-building materials of our food, though they also furnish 
 energy, (2) the carbohydrates, principally starch and sugars, found 
 mainly in the endosperm, and serving the body as fuel to produce 
 energy for warmth and muscular work; (3) the fats, occurring princi- 
 pally in the germ of the grain, and being valuable to the body as fuel, 
 and (4) mineral matters, seen in the ash, especially that of the bran, 
 and providing material for bones, teeth, etc. We must also bear 
 in mind that it is not only the chemical composition of a substance 
 which determines its food value, but also the amount of nourishment 
 which the digestive organs can extract from it — in other words, its 
 digestibility. 
 
 The abundant cellulose in the bran and the coloring matter in the 
 testa tend, if left in the flour, to give it a coarse, dark character 
 very detrimental to the appearance of the bread. Accordingly, until 
 recently, that flour was quite generally considered the best which had 
 the least of the bran in it. Lately, however, much stress has been laid 
 on the nutritive value of the mineral matters and the cerealin of the 
 bran, consequently a great effort has been made to get a fine flour which 
 
11 
 
 shall include the entire wheat grain. Such flour can not produce as 
 white a loaf, and, what is still more to the point, it is doubtful whether 
 the cerealin is thoroughly digested by the human stomach; moreover, 
 the sharp, rough particles of the cellulose in the bran are said to irri- 
 tate the membranes of the alimentary canal and thus to hasten the 
 passage of the food through the intestines. This would tend to dimin- 
 ish its digestibility, although it might be advantageous in counteracting 
 a tendency to constipation. It would seem, then, that the value of 
 bran in flour, unless it can be ground more finely than at present, is at 
 least questionable. The germ, though rich in fat and ash, is also of 
 doubtful value in the flour, as it tends to darken the color, and its fat 
 occasionally grows rancid and spoils the taste. 
 
 The endosperm is by far the most important contributor to the flour. 
 In its starch lies the chief nutritive ingredient of bread. The gluten, 
 as the principal nitrogenous constituent of wheat is called, is equally 
 necessary; mixed with water it forms a tenacious, elastic body which 
 expands under the pressure of the gas from the yeast until the dough 
 is full of gas-filled holes whose walls of tough gluten do not allow the 
 gas to escape, and thus make the dough light and porous. The more 
 gluten a flour holds, the more water it can be made to take up in dough, 
 and the greater will be the yield in bread from a given amount of flour. 
 Hence flours are classified as "strong" or "weak" according to the 
 proportion of gluten which they contain and their consequent ability to 
 yield bread. Gluten has also a high nutritive value as an easily 
 digested proteid. 
 
 ■ Milling. — When people first began to grind their grain, they did so 
 simply by crushing it between any two stones which happened to he 
 handy; a little later they kept two flat ones especially for the purpose, 
 one of which they soon learned to keep stationary while the other was 
 turned about on it. At first each woman ground the meal for her own 
 family on her own stone; but after treadmills, windmills, and, later, 
 water wheels came into use all the grinding was done by the profes- 
 sional miller in the village mill. In feudal days the lord forced his 
 tenants to have their grain ground in his mill, even to bake their bread 
 in his oven, and charged a good round toll for the use of each. Vari- 
 ous devices for grinding and sifting the grain have gradually been 
 invented, until to-day we have mills covering acres of ground and 
 doing apparently impossible things with the grain. In Hungary the 
 old Roman system of cylinder milling, similar in principle to an ordi- 
 nary coffee mill, has been developed, but elsewhere the systems which 
 are known as high and low milling are more common. Here we have 
 the original system of crushing between two stones, or rollers, but so 
 elaborated as to be almost unrecognizable. In low milling the grain is 
 ground in one process between two crushers placed as near together 
 as possible. Graham flour and that commonly known as "entire- 
 
12 
 
 wheat flour" are prepared in this way. Of these only the former, 
 invented by the American physician, Dr. Sylvester Graham, really 
 contains the entire grain ; it is made by simply washing and cleaning 
 the grain and then grinding it between two stones or rollers, whose 
 surfaces are so cut as to insure a complete crushing of the grain. 
 Entire-wheat floui- is made in much the same way, except that after 
 being washed the grains are run through a machine which removes 
 the three outer layers, and then are ground. In this way the suppos- 
 edly valuable cerealin layer is included without the almost useless 
 cellulose~of the outer bran. In high roller milling the grain is washed 
 and skinned as in milling entire wheat, and then is run through five or 
 even more pairs of rollers, each successive pair being set a little nearer 
 together than the last. After each grinding, or "break," as the miller 
 terms it, the meal is sifted, and the leavings of each sifting, called 
 "tailings/' are themselves ground and sifted several times. In a mill 
 where the grain goes through a series of six straight breaks, there 
 are as many as eighty direct milling products, varying in quality from 
 the finest white flour to pure ground bran. Careful millers always 
 try to grind as near the cerealin layer as possible, and to leave as much 
 of the germ in the flour as is consistent with a good col6r. To make 
 sure that each product is up to the standard set up for it in the mill, 
 samples of it are tested every hour and the milling is regulated 
 accordingly. 
 
 The so-called "straight-grade" flours ordinarily seen on the market 
 consist of the siftings of all the breaks plus the first product of the 
 first tailings.. "Patent" and "baker's," or "household," flours are 
 varieties of the straight-grade flours. The accompanying tables show 
 the chemical composition of various milling products and American 
 wheat flours: 
 
 Analyses of wheat and the products of roller milling.^ 
 
 Water. 
 
 Protein. 
 
 Fat. 
 
 Carbohydrates. 
 
 starch, 
 etc. 
 
 Crude 
 fiber. 
 
 Wheat as it enters the mill 
 
 First break 
 
 Sixth break 
 
 Bran 
 
 Tailings from reduction No. 5. . 
 
 Second germ 
 
 Entire-wheat flour 
 
 Graham flour 
 
 Patent roller-process flour: 
 
 Bakers' grade 
 
 Family and straight grade. 
 
 High grade 
 
 Low grade 
 
 Per cent, 
 9.66 
 8.23 
 7.66 
 10.91 
 12.12 
 8.75 
 11.4 
 11. S 
 
 11.9 
 12.8 
 12.4 
 12.0 
 
 Per cent. 
 14.18 
 14.18 
 16.28 
 16.28 
 16.63 
 33.25 
 13.8 
 13.3 
 
 13.3 
 10.8 
 11.2 
 14.0 
 
 Per cent. 
 2.61 
 2.68 
 5.34 
 5.03 
 3.85 
 15.61 
 1.9 
 2.2 
 
 1.5 
 1.1 
 1.0 
 1.9 
 
 Per cent. 
 69.94 
 71.56 
 59.42 
 56.21 
 63.93 
 35.19 
 71.0 
 70.5 
 
 72.0 
 74.6 
 74.7 
 70.4 
 
 Per cent. 
 1.70 
 1.62 
 5.60 
 5.98 
 1.18 
 1.75 
 .9 
 
 .7 
 .2 
 .2 
 
 Percent. 
 1.91 
 1.73 
 5.68 
 5.59 
 2.29 
 5.45 
 1.0 
 1.8 
 
 .6 
 .5 
 .5 
 .9 
 
 1 U.S. Dept. Agr., Division ot Chemistry Bui. 13, 
 Bui. 28 (rev.ed.), pp. 57,58. 
 
 pp. 1226-1228, and Office of Experiment Stations 
 
 If, as often happens, it is desirable to blend two kinds of wheat in 
 order to obtain a flour with the average of their qualities, the grains 
 
13 
 
 are usually mixed before milling. Sometimes the miller, or even the 
 baker, mixes two pure flours, but such a proceeding is less reliable. 
 
 Very complicated chemical tests are necessary to determine the exact 
 quality of a flour, but there are certain general rules by which a good 
 Ijread flour may be judged ofl'hand. Its color should be white with a 
 faint yellow tinge; after being pressed in the hand it should fall loosely 
 apart; if it stays in lumps it has too much moisture in it; when rublted 
 between the fingers it should not feel too smooth and powdery, but its 
 individual particles should be vaguely distinguishable; when put 
 between the teeth it should "crunch" a little; its taste should be sweet 
 and nutty without a suspicion of acidity. 
 
 Impurities and falsifications of wheat flour. — The impurities which 
 may accidentally slip into a bag of grain, or even into the flour made 
 from it, consist chiefly of the seeds of other plants, and of blighted 
 or molded wheat. The foreign seeds most to be dreaded are perhaps 
 cockles and darnel, and both should be carefully guarded against — 
 cockles because they injure the color of flour and bread, and darnel 
 because it is commonly regarded as poisonous. Other foreign seeds 
 may not be equally dangerous, but they should be removed with equal 
 care, as they lessen the nutritive value and the strength of the flour. 
 Molds and other fungus growths often give a musty odor and taste to 
 grain or flour which has been kept in a damp place. Both these classes 
 of impui'ities are easily avoided by careful milling and storing, and 
 are not so much to be feared as the foreign substances which are added 
 to the flour to cheapen its cost or improve its appearance. Those used 
 to cheapen the cost are usually rye flour, corn (maize) flour, rice meal, 
 potato starch, and meals from various leguminous plants, such as peas 
 or beans. They are not harmful in the food and sometimes improve 
 the color of the bread; nevertheless they are fraudulent because they 
 lower the quality of the flour without harming its appearance. The 
 mixture is sold as flour, and thus the purchaser secures an adulterated 
 article under a false name, and often at the same price as pu re goods. 
 Mineral substances, such as alum, borax, chalk, carbonate of magnesia, 
 bone, etc. , are occasionally put into the flour to whiten it or to neutral- 
 ize its acidity, but as these are more often used by the baker than by 
 the miller, their effect will be discussed later (p. 31). 
 
 BYE. 
 
 The grain of rye is darker in color than that of wheat, but is other- 
 wise similar in appearance. It differs, however, in one important 
 particular — its gluten has not the same elastic, tenacious quality and 
 does not yield so light and well-raised a loaf. Although this fact and 
 its dark color make it less desirable than wheat flour, it is second in 
 importance as a breadstuff. It is more easily cultivated than wheat, 
 especially in cold countries, and consequently costs less. In many 
 parts of Europe it practically replaces wheat among the poor and in 
 
14 
 
 the rations furnished the army. When it is milled entire, as it usually 
 is, it contains more protein than wheat flour, but is probably less com- 
 pletely digested. Wheat and rye flour are often used together in 
 bread. 
 
 BABLEY AND OATS. 
 
 These cereals are so seldom used in bread that a short description of 
 them will suffice. In general structure their grains are not unlike 
 those of wheat; in barley the proportion of the bran to the entire 
 grain is about 21 to 79, in oats 44 to 66; the percentage of moisture in 
 them is much lower than in wheat; their gluten is even less tenacious 
 than that of rye; though flours made from them without bran contain 
 a high proportion of nutritive ingredients, they also contain a large 
 amount of indigestible cellulose and are quite unsuited to yield a light, 
 attractive bread. 
 
 COBN, OB MAIZE. 
 
 This cereal, commonly known to us as Indian corn, and on the Con- 
 tinent of Europe as maize, or Turkish wheat, is a native of America. 
 It is commonly grown in North and South America, northern Africa, 
 India, and southern Europe, especially Italy and the Balkan regions, 
 and is slowly being introduced into other European countries. The 
 skin of the kernel is thin and tender, the endosperm abundant, white, 
 and mealy, the germ comparatively large. See fig 2. The kernels are 
 generally white or j^ellow. Compared with wheat, maize is rich in fat, 
 
 poorer in cellulose and protein, and about 
 equal in carbohydrates, mineral matters, 
 and moisture. Most of its fat is in the 
 embryo or germ, which is often removed 
 in milling to prevent the flour or meal 
 becoming rancid. Maize flour makes 
 very nutritious and appetizing unleav- 
 ened bread, hoecake, johnny cake, etc., 
 but this dries so quickly that it must be 
 eaten fresh. Maize flour contains no 
 tenacious gluten -like proteid, and there- 
 fore can not be used alone to produce a 
 good loaf raised with yeast. Much corn 
 bread and other foods made from corn 
 meal are eaten in the United States. In 
 Italy corn-meal mush, or "polenta," as 
 it is called, forms the principal article 
 of diet of the peasants in large districts 
 throughout a considerable part of the 
 year. In Servia the unripe corn is eaten much as we use it, and corn- 
 meal bread and mush are staple articles of diet. 
 
 Fig. 2. — Section of grain of corn : a, skin 
 and testa; b, membrane; c, embryo; d, 
 endosperm: /, scutellum. 
 
15 
 
 RICE, MILLET, BUCKWHEAT, ETC. 
 
 Rice is a very important cereal in China, Japan, and other oriental 
 countries; much millet is eaten in China, India, and Russia; sesame is 
 also largely used by the native races of India, and in the United States 
 buckwheat is often made into batter cakes; but none of these-as a rule 
 take the place of bread to any extent except in some oriental countries. 
 In some regions of Russia, however, buckwheat porridge is the prin- 
 cipal cereal food. Kafir corn is used in the United States to a limited 
 extent for batter cakes, etc., though in its native land it is the princi- 
 pal cereal of large numbei's of Abyssinians, Kafirs, and other races. 
 
 The following table gives figures by which the chemical composi- 
 tion of our most common cereals may be easily compared: 
 
 Composiiion of cereals.^ 
 
 Water. 
 
 Protein. 
 
 Fat. 
 
 Carbohydrates. 
 
 Starch, 
 etc. 
 
 Crude 
 fiber. 
 
 Ash. 
 
 Barley 
 
 Buckwheat 
 
 Corn (maize) 
 
 Kafir corn 
 
 Oats 
 
 Rice 
 
 Rye 
 
 Wheat: 
 
 Spring varieties. 
 
 Winter varieties 
 
 Per cent. 
 10.9 
 12.6 
 9.3 
 16.8 
 11.0 
 12.4 
 11.6 
 
 10.4 
 10.5 
 
 Per cent. 
 
 12.4 
 
 10.0 
 9.9 
 6.6 
 
 11.8 
 7.4 
 
 10.6 
 
 12.5 
 11.8 
 
 Per cent. 
 1.8 
 2.2 
 2.8 
 3.8 
 5.0 
 .4 
 1.7 
 
 2.2 
 2.1 
 
 Per cent. 
 69.8 
 64.5 
 74.9 
 69.5 
 69.7 
 79.2 
 72.0 
 
 71.2 
 72.0 
 
 Per cent. 
 2,7 
 8.7 
 1.4 
 1.1 
 9.5 
 .2 
 1.7 
 
 1,8 
 1.8 
 
 Per cent. 
 2.4 
 2.0 
 1.5 
 2.2 
 3.0 
 .4 
 1.9 
 
 1.9 
 1.8 
 
 1 U. S. Dept. Agr., Office of Experiment Stations Bui. 11, pp. 16, 17, and Bnl. 28 (rev. ed.) , p. 56. 
 
 YEAST AND OTHER LEAVENING AGENCIES. 
 
 THE THEORY OP FERMENTATION. 
 
 When, in beer making, a little yeast is put into a vat of warm, sweet 
 liquid, bubbles gradually appear until the whole mass seems to be 
 boiling. If the liquid is analyzed after the yeast has so worked in it 
 for a time it will be found to contain less sugar than at first; the 
 amount of yeast will have increased, and alcohol and carbon dioxid 
 will appear in considerable quantities. The explanation is this: The 
 yeast, which is really a mass of tiny plants, has reproduced again and 
 again, and in this growth has fed upon the sugar of the liquid and given 
 off alcohol and carbon dioxid. Such a phenomenon is called alcoholic 
 fermentation, and is essentially the same as that which "raises" a loaf 
 of bread. Such fermentation is by no means the onlj"^ kind which 
 occurs in common life. The souring of cider into vinegar, for instance, 
 is due to another kind. In that case a variety of microscopic plant 
 develops in the cider, and in so doing produces acetic acid, which gives 
 vinegar its characteristic taste. This is called acetic fermentation. 
 Similarly, if another variety of bacteria get a chance to develop in 
 
16 
 
 sweet milk ttey give rise to lactic fermentation, during which is pro- 
 duced the lactic acid which turns the milk sour. Rancidity of butter 
 is due to the so-called butyric fermentation. Here the bacteria yield 
 butyric acid, which gives the butter its disagreeable taste and odor. 
 
 These microscopic plants and many others are widely distributed in 
 the air, and often find their way accidentally into different materials, 
 where they grow and multiply, causing fermentation, just as thistle 
 seeds, for instance, are blown about in the air until they lodge in some 
 favorable spot and grow. At other times special forms of ferments in 
 so-called "pure cultures" are purposely added to some material, just 
 as seeds of larger plants are purposely sown in the gai-den. Thus 
 pure cultures of certain microscopic organisms are added to cream 
 to improve the flavor of butter and make it uniform in quality. This 
 insures a special fermentation instead of the accidental fermentation 
 which would otherwise occur. The term fermentation was first 
 applied to the action of yeast plants on sugar with the formation of 
 carbon dioxid and alcohol. There is another class of chemical changes 
 to which the term fermentation is applied. Such changes are produced 
 by chemical substances called enzyms, which are not living organisms, 
 but which are produced by living organisms. Ferments are therefore 
 divided into two classes, (1) the organized ferments, such as yeast, 
 bacteria, etc., and (2) unorganized ferments, or enzyms. Human saliva 
 contains an enzym called ptyalin. When mixed with food in the mouth 
 it changes starch into a form of sugar, which is more easily digested 
 than starch. In grain there exists an enzym called diastase, capable of 
 producing a similar effect on starch. The pepsin and trypsin of the 
 digestive juices are also enzyms. 
 
 It is a peculiar feature of fermentation that the microscopic plants 
 which cause it affect a much larger amount of the material on which 
 they feed than goes to their own development. Thus yeast converts 
 much more sugar into alcohol and carbon dioxid than it consumes in 
 its own growth and reproduction. When the fermentation ceases 
 the yeast plant remains; in other words, the fermentation has been 
 produced without changing the nature of the agent producing it. In 
 the same way the enzyms cause fermentation without being themselves 
 changed. Though so much has been learned in recent years concern- 
 ing fermentation, there still remain many things to be explained. We 
 know what changes take place and under what conditions, but just why 
 they take place is not so clear. It is a remarkable fact concerning 
 ferments that the substances they produce, in time put a stop to their 
 activity. Thus the alcohol produced by the yeast in time is sufficient 
 to hinder the growth of the yeast plant and ultimately to kill it. If, 
 however, the products of this activity are removed, the ferments resume 
 work. 
 
n 
 
 ^ d® 
 
 
 
 QL 
 
 'S\jd) 
 
 YEAST. 
 
 Keeping the above facts in mind, it is easy to understand the leaven- 
 ing effect of yeast in dough. The yeast, " worlting " in the warm water 
 and flour, feeds on sugar ^ originally present or else produced from the 
 starch by diastase, grows and spreads throughout the dough, at the 
 same time giving off carbon dioxid gas, which forces its way between 
 the tenacious particles of gluten and lightens the dough. 
 
 Scientifically speaking, yeast is a minute fungus of the genus Saccha- 
 romyces. A single plant is a round or oval one-celled, microscopic 
 body (fig. 3), which reproduces in two ways — either by sending out buds 
 which break off as new plants, or by forming spores which will grow 
 into new plants under favorable conditions. It grows only in the pres- 
 ence of moisture, heat, and nutritive material. If the moisture is not 
 abundant the surrounding 
 substances absorb that which 
 already exists in the yeast 
 cells and so prevent them from 
 performing their functions. 
 Yeast develops best at a tem- 
 perature of 77°-95° F. (25°- 
 35° C). We have already 
 seen how yeast uses up sugar 
 in its growth. It is also be- 
 lieved that some nitrogen is 
 necessary for the best devel- 
 opment of yeast and that such 
 development is most complete 
 in the presence of free oxygen , 
 l)ut why these things are so is 
 
 not yet clearly understood. '^"'- ^--Yea^st plant highly magnified. 
 
 Yeast is literally as old as the hills. It must be present in the 
 atmosphere, for if a dish of malt extract, originally free from yeast, 
 be exposed to the air, alcoholic fermentation, such as could be pro- 
 duced only by yeast, will soon set in. Such yeast is known as "wild 
 yeast" and all our yeasts have been cultivated from it. The oldest 
 method of growing yeast is perhaps that used by the Egyptians. A 
 little wild yeast was obtained and set in dough, a portion of which was 
 
 fF 
 
 
 ■0 
 
 
 ^ 
 
 .^-p^ 
 
 -<-^o ^^ 
 
 
 'The sugar upon which yeast is said to feed in its growth is not necessarily such 
 sugar as we ordinarily use to sweeten our food. The word sugar is here used in its 
 broader, scientific sense. All starches and sugars, it will be remembered, are grouped 
 together by chemists under the name of carbohydrates. They are chemical corii- 
 pounds of carbon, oxygen, and hydrogen and differ from each other in the proportion 
 of oxygen and hydrogen to carbon which they contain. For a more extended 
 discussion of sugar see U. S. Dept. Agr., Farmers' Bui. 93. 
 
 15010— No. 112 —2 
 
18 
 
 saved from the baking; there it went on developing as long as mate- 
 rials held out, and thus the bit of dough or ' ' leaven " contained so much 
 yeast that a little of it would leaven the whole loaf. It was such leaven 
 as this which the Israelites had not time to put into their bread when they 
 were brought out of the land of Egypt. A microscopical examination 
 was recently made of some bread over four thousand four hundred years 
 old, found in Egypt, with other remains of a long-vanished people. It 
 was made of ground barley and the yeast cells were plainly visible. 
 A similar process of raising bread with " leaven" is still carried on in 
 some regions of Europe. The " wet " or "potato yeast," so common in 
 this country before the days of patent yeast, was made by a similar 
 method. Wild yeast was cultivated in a decoction of hops or potato 
 and water and some of the material thus obtained was mixed with the 
 dough. The "barms" so much used in Scotland are made by letting 
 yeast grow in malt extract and flour (p. 22). Brewers' and distillers' 
 yeasts are taken from the vats in which malt extract has been ferment- 
 ing. Compressed yeasts are made by growing yeast plants in some 
 sweet liquid, then drying the material to check their growth, and 
 pressing it; sometimes a little starch is added to make the little cakes 
 keep their shape. The strength of any yeast depends on the care with 
 which it is made and preserved. Ordinary brewers' yeasts are likely 
 to be full of the bacteria which set up lactic or other fermentations in 
 the bread and give it a disagreeable taste and odor. They are very 
 susceptible to changes in the weather and can not be always relied on. 
 Compressed yeasts, if carefully made, are more uniform in strength 
 and composition. Usually a few of the microscopic plants or bacteria 
 other than yeast are allowed to remain, as the slight acid taste they 
 give to the bread is considered an advantage. 
 
 SUBSTITUTES FOR YEAST. 
 
 Partly because yeast is uncertain in its workings, partly, too, 
 because it uses up some of the nutritive ingredients of the bread by 
 feeding upon them, attempts have been made to find some substitute for 
 it. Various chemicals have been used to produce carbon dioxid gas in 
 the dough. The first noteworthy attempts were made about fifty 
 years ago at Harvard University and in Germany. Yeast powder, 
 as the American preparation was called, was a mixture of an acid and 
 an alkaline powder — the former calcium phosphate and the latter 
 bicarbonate of soda and potassium chlorid. When duly mixed with 
 the dough these -were supposed to give off carbon dioxid as effect- 
 ively as yeast. Liebig, who calculated that in Germany the daily loss 
 of material by the growth of the yeast plant was, if saved, sufficient 
 to supply 400,000 persons with bread, made a great effort to intro- 
 duce a similar preparation into Germany, but with little success. 
 
19 
 
 Numeroiis baking powders made from various chemicals are in the 
 market now. The self-raising flour used in the United States Army- 
 is a flour ready mixed with such a preparation. The chief objections 
 to such yeast substitutes are that unless carefully prepared they may 
 be inefficient or harmful, that they are easily adulterated, and that 
 bread made from them is usually rather tasteless, lacking the flavor and 
 aroma which good yeast imparts. Soda, cream of tartar, or saleratus 
 biscuits are made on the same principle, but with less powerful leaven- . 
 ing agents. 
 
 The "aerated bread" so popular in London is made by a different 
 method, invented by the English physician Dauglish in 1856. Accord- 
 ing to this method, the water used for wetting the dough is directly 
 charged with the requisite amount of carbon dioxid gas and then 
 mixed with the flour in a specially constructed machine. Sometimes 
 a little fermented barley infusion or wort, as it is called, from a 
 brewery, is put into the water. This aids it in absorbing the gas, 
 renders the gluten more elastic, and improves the flavor of the bread. 
 
 The so-called "salt-rising" bread is interesting as an illustration of 
 self -raised bread. In it the ferments originally present or acquired 
 from the air produce the fermentation which leavens it. To make it, 
 warm milk and corn meal are mixed together into a stiff batter, which 
 is left at blood heat until the whole mass is sour; that is, until the fer- 
 ments present have produced fermentation throughout. Next a thick 
 sponge is made of wheat flour and hot water, in which a little salt has 
 been dissolved. This sponge and the sour batter are thoroughly 
 kneaded together and set in a warm place for several hours. The 
 leavening action started in the batter spreads through the dough and 
 produces a light, porous loaf, which many persons consider very 
 palatable. Such bread is quite free from acidity, as the presence Of 
 the salt prevents undesirable fermentation. 
 
 RAISED BREAD. 
 
 Ordinarily a baker mixes his dough with water, and most of the 
 experiments and analyses quoted here have been made with such bread. 
 Sometimes, especially in private families, milk is used in the place of 
 water. Such dough is slower in rising, but makes an equally light 
 loaf. Milk bread naturally contains a larger percentage of proteids 
 and fats than water bread and is equally digestible. Its use is by all 
 means to be advocated, especially on farms where skim milk is abun- 
 dant. ' When water is used it should, of course, be as pure as possible. 
 Its hardness or softness makes little difference in the quality of the 
 bread, though perhaps the softer water is to be preferred. Salt is used 
 in bread because it imparts a flavor without which bread is usually 
 
 'See articles on the digestibility of bread in Maine Sta. Ept. 1898. 
 
20 
 
 considered insipid, and because it exerts a retarding influence on 
 the chemical process by which starch is converted into sugar and on 
 fermentation. 
 
 PREPARATION OF THE DOUGH. 
 
 There are various methods of mixing dough, but certain general 
 rules apply to them all. As yeast develops best at a moderately high 
 temperature (77°-95° F.), the materials of the dough should be at least 
 lukewarm, and the mixing and the raising should be done- in a warm 
 place, as free as possible from drafts. If all portions of the dough are 
 to be equally aerated by the gas from the growing yeast, the latter must 
 be thoroughly mixed with the flour and water; moreover, as the pres- 
 ence of oxygen aids the growth of the yeast, all parts of the dough 
 should be exposed to the air; both these results are accomplished 
 by the kneading. Too little yeast will, of course, yield a badly raised 
 loaf, but too much yeast is just as dangerous; the .bubbles formed in 
 the gluten of the flour, unable to resist the pressure of the excessive 
 amount of gas, break open, the gas escapes, and the dough becomes 
 heavy and soggy. Too much yeast also gives an unpleasant, " yeasty" 
 taste to the bread, due partly to the presence of superfluous yeast 
 cells, but more especially to other microscopic growth producing fer- 
 mentations. Even when used in small quantities yeast has a decided 
 influence on the flavor of the bread. The amount of yeast which 
 should be used depends on the strength of the flour. A flour in which 
 the gluten is abundant and tenacious can resist a much stronger pres- 
 sure of gas than one poor in gluten, which, if it does not fall entirely, 
 is likely to make a loaf with large holes and heavy, badly raised masses 
 between. Similarly, the proportion of water which should be used 
 varies with the strength of the flour. The standard cookbooks sug- 
 gest an average of about three parts of flour to one of water, the 
 ratios changing with the quality of the flour. In general, nothing but 
 practical experience with his materials can teach a baker the exact 
 quantities which he should mix. Salt, as has been said, tends to retard 
 fermentation, and consequently should be added toward the end of the 
 mixing;- then it is useful because it checks lactic or butyric fermenta- 
 tions, such as often follow the alcoholic fermentation. 
 
 It seems almost superfluous to say that the greatest cleanliness 
 should be observed in kneading bread. Most household cooks main- 
 tain that it is impossible to mix dough as evenly with a knife or spoon 
 as with the hands. Perhaps, where bread is made in small quantities 
 and every precaution is taken against unclean liness, this use of the 
 hands may be tolerated, but not in wholesale bakeries where dough is 
 mixed in such large quantities that the kneading is violent physical 
 exercise and the worker is unable to take his hands from the dough 
 long enough to wipe his dripping forehead. In such establishments 
 
21 
 
 the modern kneading machines, in which revolving metal blades do 
 the work of the hands, are surely to be advocated, and in general 
 those breads are to be recommended which are made with the aid of 
 machiner3' so arranged that none of the materials need be touched by- 
 hand from the time they enter the bakery until the finished loaves are 
 taken from the oven. Every utensil used for bread making should be 
 scrupulously clean, not only on principles of general decency, but 
 because otherwise bacteria may get into the dough and produce 
 harmful fermentation. 
 
 The ways of mixing dough most used in this country by bakers are 
 probably those known as " straight dough " and " sponge dough." 
 
 Straight dough, or "offhand" dough, as it is sometimes called, is 
 made by mixing all the materials at one time, and then setting the 
 mass in a warm place to rise for ten hours or more before baking. It 
 requires more yeast and stronger flour than other methods in which 
 the yeast is allowed to grow in an especially favorable medium before 
 being mixed with the main dough, and needs a longer time to rise, but 
 on the other hand gives an unusually large yield in bread. It is con- 
 venient in family bread making, especially when strong, compressed 
 yeast is used, as the dough can be mixed overnight and baked in the 
 morning. Some wholesale bakers dislike it because the dough is stiff 
 and hard to knead, because the large quantities of materials used at 
 one time require extensive kneading apparatus, and because the bread 
 is usually coarse in texture, with a raw, grainy taste, due to the strong 
 flours used. 
 
 Sponge dough. — This method is best adapted to fancy working, and 
 makes equally good crusty loaves or light biscuit. To make the 
 "sponge," as the bread mixture is commonly called, the yeast is 
 allowed to work for eight or ten hours in a portion of the flour or 
 water. This is then mixed with the remaining materials and left to 
 rise a few hours before baking. The sponge is "slacker" — that is, 
 contains more moisture than offhand dough — and thus gives the yeast 
 a better chance to work. Bakers usually set their sponge with a strong 
 flour, which gives a light, elastic quality; a little salt is put into it to 
 prevent lactic fermentation. A weaker flour may be used in the second 
 mixing, as the greater part of the gas has already been given off in the 
 sponge, and no great pressure will come on the newly added gluten. 
 If strong flour be used instead, the bread yield will be greater, but the 
 soft, sweet flavor imparted by the weaker kinds will be replaced by the 
 harsh taste noticed in bread made from offhand doughs. Great care 
 must be taken to mix the second lot of flour in thoroughly, or the bread 
 will be full of hard lumps on which the yeast has had no effect. Sponge- 
 made bread usually rises evenly and well, and can be worked into 
 almost any shape. It has the further advantage of keeping well. It 
 requires longer labor than the method described before, still the dif- 
 
22 
 
 ference is really that between two short kneadings in soft dough and 
 one long one in stiflP. Like oflfhand dough, it can be started the night 
 before it is baked. 
 
 After mixing his dough in the way he considers most desirable, the 
 baker sets it in a warm place to rise. Here the yeast continues to 
 work and the gas given oflf stretches the spaces between the particles 
 of dough. If the gas is allowed to go on increasing until its pressure 
 is greater than the elasticity of the gluten can resist, the latter breaks 
 apart, leaving large holes throughout the dough. If such "over- 
 proved" dough is kneaded a little before it is put into the oven the 
 excessive gas will be forced out and the holes will be more regular. 
 
 Besides the methods of bread making noted above there are others 
 occasionally used. Jago' describes those employed by bakers in 
 England and Scotland. The following statements are based on his 
 description: 
 
 Ferment, sponge, and dough method. — As the name implies, this is a 
 combination of the two methods last described. The ferment is mixed 
 with the sponge, then, after this has stood for several hours, the rest 
 of the flour and water are mixed in the sponge and dough fashion. 
 There is, perhaps, a slight economy of yeast by this method, but it is 
 very complicated, and therefore less certain. 
 
 A similar proceeding is sometimes practiced in the southern part of 
 the United States, and is known as a "bleaching process," because the 
 long rising is supposed to whiten the dough. 
 
 Scotch barm method. — ^This is not unlike the ferment, sponge, and 
 dough system, "barm " taking the place of the other ferments. Barm 
 is literally the foamy scum which rises to the top when beer, etc. , is 
 made. This may be used to ferment other materials. A varietj' of 
 yeast is also called barm. To make barm in the household malt is 
 crushed in warm water, hops and boiling water are poured over it, then 
 flour is added, and the mixture is allowed to stand until the starch 
 granules from the flour have been burst op6n by the hot water and 
 the starch thus freed has been changed into sugar by the diastase of 
 the malt. A sweet liquid is drained off from this and mixed with flour 
 and water, the resulting sticky mass being subjected to the action of 
 yeast, either acquired spontaneously by exposure to the air (virgin 
 barm) or added in the form of a little old barm or ordinary yeast 
 (Parisian barm). The fermentation thus started is allowed to continue 
 several days and then the barm is ready for use in the sponge. A 
 strong flour is needed for both the barm and the dough, and conse- 
 quently the bread yield is large. In Scotland, where this method is 
 almost universal, bakers consider it most economical, because there is 
 practically no yeast to be bought and the flour used in the barm goes 
 
 'The Science and Art of Breadmaking, by William Jago, London, 1895. 
 
23 
 
 into the bread. These arguments seem hardly tenable, however. The 
 cost of labor in preparing the barm must be considerable and at least 
 a portion of the flour in the barm is lost in the form of alcohol and 
 carbon dioxid. Moreover, while the barm is exposed to the air in mak- 
 ing it takes in a great many bacteria which start lactic and other fer- 
 mentations and give a decidedly sour taste to the bread. To be sure, 
 persons accustomed to such bread find an ordinary sweet loaf insipid. 
 Still such a flavor would, it is probable, hardly be acceptable to the 
 average American palate. 
 
 BREAD MADE WITH LEAVEN. 
 
 According to Boutroux,^ the leaven used in France is easily prepared. 
 A little of the dough ready for baking is saved and mixed with an 
 equal amount of flour and water and is allowed to stand four or five 
 hours; this operation is repeated three or four times before the leaveji 
 is ready to be mixed into the actual dough. This gradual mixing of 
 the leaven is preferred, because in this way the yeast is allowed to act 
 on one lot of flour only for a short time, then before it has become 
 exhausted and other fermentations set in new yeast food is added, and 
 thus a large number of yeast cells is supposed to be produced along 
 with relatively few lactic and butyric bacteria. In spite of this pre- 
 caution, bread made with leaven has a much more acid taste than that 
 made with yeast, especially if the leaven has been kept some time. 
 Anyone who has eaten the bread ordinarily made by the poor country 
 people of France or Switzerland will willingly testify to this. More 
 leaven is required in winter than in summer, because the yeast devel- 
 ops less quickly in cold weather, but on the average the leaven, should 
 form one-third of the entire dough. Bread made with leaven has large, 
 irregular holes in its crumb. This is attributed to the fact that the 
 bacteria in the leaven give rise to a f ennent (diastase) and acids, which 
 tend to soften the gluten. 
 
 Boutroux considers bread made with leaven more healthful than that 
 made with yeast, because the acids it contains aid in its digestion. He 
 also maintains that leaven is more reliable than the yeasts ordinarily 
 found in the French market, but probably the majority of experts in 
 this country would hold that the best of our compressed yeasts are 
 more reliable and much more convenient. Whatever its practical 
 value nowadays, bread made from leaven is interesting from the his- 
 torical point of view, as it represents the way in which almost all the 
 world made its bread from the time of the Pharaohs down to our own 
 century. The following description '' of bread making, as practiced by 
 
 ' Le Pain et la panification. L. Boutroux, Paris, 1897. 
 
 'The Dawn of Civilization. Egypt and Chaldaea. G. Maspero. London: Soc. 
 Prom. Ohristiaa Knowledge, 1897, 3 ed., p. 320. 
 
24 
 
 a woman of ancient Egypt, shows that the principle was essentially the 
 same then as now: 
 
 She spread some handfuls of grain upon an oblong slab of stone, slightly hollowed 
 on its upper surface, and proceeded to crush them with a smaller stone like a painter's 
 muller, which she moistened from time to time. For an hour and more she 
 labored; * * * but an indifferent result followed from the great exertion. The 
 flour, made to undergo several grindings in this rustic mortar, was coarse, uneven, 
 mixed with bran or whole grains which had escaped the pestle, and contaminated 
 with dust and abraded particles of the stone. She kneaded it with a little water, 
 blended with it, as a sort of yeast, a piece of stale dough of the day before, and made 
 from the mass round cakes about half an inch thick and some 4 inches in diam- 
 eter, which she placed upon a flat flint, covering them with hot ashes. The bread, 
 imperfectly raised, often badly cooked, borrowed from the organic fuel under which 
 it was buried a special odor and a taste * * *. 
 
 SPECIAL BREADS. 
 
 Besides the ordinary white bread described in the last section, there 
 are innumerable fancy white breads, breads made ,from other flours 
 than wheat, and unleavened breads on the market. So few analyses 
 of them have been made, however, that they can be hardly more than 
 enumerated here. 
 
 FANCY LEAVENED BREADS. 
 
 Most like the ordinary white bread are of course the fancy white 
 ones, Vienna and French rolls, milk breads, etc. These usualh' differ 
 chiefly in the use of milk, sugar, butter, lard, etc., in the dough. 
 Entire wheat, graham, rye, barley, or oatmeal flours are made into 
 bread in essentially the same way, and vary in texture and nutritive 
 value according to their original composition. Soda, cream of tartar, 
 or baking powder biscuits, shortcakes, etc., are intrinsically the same 
 thing as ordinary white bread, except that the baking powder or its 
 substitute does the work of yeast. Such breads do not require to be 
 kneaded or set to rise, and bake very quickly, hence are very con- 
 venient when yeast is unobtainable or time is short. They never 
 become so light and porous as yeast-made bread, however, and dry 
 very quickly. 
 
 UNLEAVENED BREADS. 
 
 The most interesting of these is perhaps the passover bread, which 
 has been used during passover week by orthodox Jews from the time 
 of Moses until now. It is simply a mixture of flour and water, baked 
 in small round cakes until it is dry and hard, and is not unlike plain 
 water crackers. Pilot bread, or ship's biscuit, is another simple prep- 
 aration of flour and water so cooked that it can be kept for any 
 length of time. Crackers, or biscuits, as they are often called, especi- 
 ally in England, are also a variety, or, more correctly, innumerable 
 
25 
 
 varieties, of unleavened breads. Milk, butter, lard, spices, dried 
 fruits — anything or everything desired to give them 'a particular con- 
 sistency, color, or flavor — is mixed with the flour and water, and the 
 dough is then passed through very ingenious cutting machines and 
 quicldy baked in a hot oven. Such crackers are a concentrated form 
 of nourishment. 
 
 The original graham bread made without yeast from graham flour 
 according to the receipt of its inventor, and not to be confounded with 
 raised graham bread, is made by kneading the flour and water thor- 
 oughly, and allowing the dough to stand several hours before baking. 
 It is heavier than ordinary yeast bread, but still has a few "holes" in 
 it, due probably to fermentation started by bacteria accidentally pres- 
 ent in the flour or the air; it is sweet and by no means unpalatable, 
 but probably the nutritive value of its protein is lower than Dr. Graham 
 supposed. 
 
 Gluten bread, as its name implies, contains the gluten of the flour 
 from which more or less of the starch has been removed. To make it, 
 strong flour and water are made into dough, which is pressed and 
 strained under a stream of water until the starch has been worked out; 
 it is then kneaded again and baked. It makes a light, elastic loaf, fre- 
 quently prescribed for diabetic patients from whose diet it is consid- 
 ered desirable to exclude starch. 
 
 HOUSEHOLD METHODS OF BREAD MAKING. 
 
 In preceding paragraphs attention has been called to the meth- 
 ods of bread making followed bj' bakers. These differ from the 
 household methods more in the quantities used than in the principles 
 followed. Thus, a baker uses a large amount of flour and finds that 
 mixing the dough and kneading it is much facilitated by machinery 
 of different sorts. With the small quantities used in the household 
 special machines for kneading, etc., are not commonly used. In dif- 
 ferent regions somewhat different ways of making bread in the house- 
 hold are popular, and, indeed, each bread maker is apt to believe she 
 has some especially valuable way of mixing, kneading, etc. These 
 differences are not as important as is sometimes supposed, and, as has 
 been said, the general principles followed in bread making at home 
 are the same as in bakeries. What are perhaps the two most popular 
 ways of making bread at home are sometimes called the "quick- 
 raising" method and the "slow-raising" method. 
 
 ftuick-raising method. — A stiff dough is made of the flour, water, 
 and yeast. It is thoroughly kneaded and is then allowed to rise until 
 it doubles its bulk, when it is again kneaded thoroughly. After rising 
 a second time it is baked. In the quick-raising process a large 
 quantity of yeast is used, and the time of fermentation is only about 
 two and a half hours. The baking is completed in about four or five 
 houi's after the bread is first started to rise. 
 
26 
 
 Slow-raising method. — A batter is made of the flour, yeast, and 
 water, which is allowed to ferment ten or fifteen hours, usually over- 
 night. More flour is then added, the dough is kneaded until smooth, 
 and then allowed to rise and is treated in the same way as in the first 
 method. In the slow-raising method less -yeast is used than in the 
 short process, and the fermentation is carried on foi- a longer time. 
 The usual temperature at which the fermentation thus takes place is 
 perhaps not far from 70°. 
 
 Various forms of "raised biscuits," "hot bread," etc., are made in 
 the household by adding shortening, milk, eggs, etc., to the dough, or 
 by modifying in some way the process followed. Sometimes baking 
 powder of some sort is used as a leavening agent instead of yeast, and 
 the form of bread called " baking-powder biscuit," or by some similar 
 name, is the result. An interesting variety of bread made without leav- 
 ening is known as "Maryland" or "beaten" biscuit. A rather stiff 
 dough is made from flour and water, or milkj with shortening and salt 
 added. It is kneaded and then beaten or pounded, being frequently 
 turned over and over until it looks light and puffy. The biscuits are 
 then formed and baked. The folding and pounding of the dough incloses 
 small quantities of air in numberless little blisters. These expand in 
 baking and make the biscuit light and porous. The different kinds of 
 bread from other grains than wheat, as "corn bread," " brown bread," 
 "rye bread," "gems," etc., which are made in many households vary 
 somewhat in different regions, but they all follow the same principles 
 which govern the bread making from wheat flour — that is, the flour or 
 meal is mixed to a dough with water or milk, and some leavening sub- 
 stance is generally added to make the dough porous. Eggs, sugar, 
 shortening, etc. , may be added, giving rise to the numerous varieties 
 with which we are ail familiar. 
 
 BAKING AND COOLING. 
 
 In the earliest days of bread making the dough was simply put into 
 the ashes of the fire to bake; then came the ovens heated by a fire 
 within, which are stiU used to some extent, and finally the elabo- 
 rately constructed ovens which can be heated or cooled to any tem- 
 perature by means of furnaces and ventilating devices around them. 
 But whatever the structure of the oven, the changes which the bread 
 undergoes while in it are essentially the same. It goes in a heavy, 
 uniform mass and comes out a light body of increased volume with a 
 crisp, dark exterior — the crust — and a firm, spongy interior — the 
 crumb. Let us first see what happens in the crvunb. This, of course, 
 heats more slowly than the outside; indeed, the moisture which it 
 contains prevents its temperature from rising much above the boiling 
 point of water (212° F.). When first put into the oven the yeast con- 
 tinues working, but a temperature of 168° F. kills it. The gas in the 
 
27 
 
 dough, however, still expands and, forcing its way outward, enlarges 
 the loaf and gives it a spongy appearance. The gluten becomes stiff- 
 ened by the heat, so that even after the gas in the bubble-like pores 
 has escaped the walls still retain their shape. The starch granules and 
 perhaps the protein compounds undergo certain chemical changes which 
 render them more digestible. Meanwhile the crust is becoming hard 
 and dark; the heat changes its starch into stiff gum and sugar and dries 
 out the moisture; the brown color is due to chemical changes known as 
 " caramelization." Of course the proportion of crust to crumb varies 
 with the size of the loaf. The accompanying table ' gives the relative 
 percentages by weight in loaves of different weight of German bread: 
 
 Comparative weight of crust and crumb in bread. 
 
 
 Weight of 
 loaf. 
 
 Crumb in 
 loaf. 
 
 Crust In 
 loaf. 
 
 Bread No 1 
 
 Grams. 
 
 398 
 
 880 
 
 1,783 
 
 1,998 
 
 Per cent. 
 55.2 
 59.7 
 64.3 
 71.2 
 
 Per cent. 
 44 8 
 
 Bread No. 2 
 
 40.3 
 
 
 35.7 
 
 Bread No. 4 
 
 28.8 
 
 
 
 The heat in the oven should not be too great, especially at first, or 
 the outside of the bread will harden too quickly and the interior will 
 not be done before the crust is thick and dark; further, the gas 
 expanding in the crumb will be unable to escape through the crust 
 and will lift up the latter, leaving great holes beneath it. To prevent 
 too rapid formation of the crust bakers often moisten the tops of their 
 loaves before putting them into the oven, or have devices for passing 
 steam over them during the baking. The steam also changes some of 
 the starch into a sort of gum on the top of the loaf and gives it the 
 shiny look so often seen in Vienna bread. The same effect can be 
 produced by moistening the top of the loaf just before it is taken from 
 the oven. If his oven is not equally heated throughout, a baker 
 usually puts his small loaves into the hottest part at first, as the crumb 
 of these bakes more quickly and is in less danger of being underdone. 
 When these are baked the larger loaves, whose crumb has baked grad- 
 ually in the cooler parts, are moved into the warmer place and their 
 crust is quickly hardened. In some large ovens the temperature is 
 gradually raised during the baking; especially is this the case in the 
 aerated bread factories. Aerated dough is mixed with cold water, 
 and if it were immediately subjected to a high temperature the crust 
 would form before the interior was more than warmed through. 
 Accordingly, a peculiar oven is used, one end of which is heated much 
 hotter than the other. Two cylinders, one at either end of the oven, 
 are connected by an endless chain, on which the bread plates are hung; 
 the dough is placed on the latter at the cooler end, and then is grad- 
 
 1 Arranged from Bimbaum's Das Brotbacken. Braunschweig, 1878, p. 255. 
 
28 
 
 ually swung over to the warmer end, the speed being regulated by 
 the time needed for baking. This insures a thorough baking of the 
 crumb, while the extreme heat at the last gives a good, crisp crust. 
 
 The temperature of an oven and the time required for baking depend 
 upon the size of the loaves. Small biscuits or rolls can stand a much 
 hotter oven and quicker baking than large loaves, which must be 
 heated slowly and long. For ordinaiy purposes a baker heats his oven 
 to 4:00°-5O0° F. and lets a pound loaf bake an hour or an hour and 
 a quarter; small rolls perhaps half an hour. An experienced cook can 
 tell when the oven is hot enough by putting the hand in, but a pyrom- 
 eter, as a thermometer for measuring high temperature is called, makes 
 a much safer guide for an ordinary person. 
 
 On being taken from the oven bread should be placed on slats or 
 sieves so that the air can circulate about it until it is thoroughly 
 cooled. By that time all the gas and steam which are likely to escape 
 have done so, and the bread may be put away. Some housekeepers wrap 
 their hot bread in cloths, but this is not advisable, not only because it 
 makes the bread "taste of the cloth," but also because it shuts the 
 steam up in the loaf and makes it damp and clammy-— an excellent 
 medium for cultivating mold. 
 
 Of course, as great cleanliness should be observed in handling and 
 marketing bread as in making it. In some bakeries it is kept where 
 the dust and dirt from the street can get to it, or sometimes bread is 
 delivered in dirty baskets or carts. In this way disease germs and 
 dirt may readily be brought into the home. In Germany this is 
 sometimes avoided by slipping the loaves into parchment-paper bags 
 as soon as they are taken from the oven. Some American bakers adopt 
 similar plans; a frequent one is that of wrapping the bread in paraffin 
 paper, which serves the double purpose of keeping out dirt and pre- 
 venting the bread from drying. 
 
 CHEMICAL COMPOSITION. 
 
 The chemical composition of the finished loaf diflPers somewhat from 
 that of the original ingredients. The following table shows the differ- 
 ence in composition between flour and bread: 
 
 Average composition of while bread and of the flour from which it was made.^ 
 
 
 Water. 
 
 Protein. 
 
 Fat. 
 
 Carbohy- 
 drates. • 
 
 Ash. 
 
 
 Per cent. 
 35.3 
 12.0 
 
 Per cent. 
 9.2 
 11.4 
 
 Per cent. 
 1.3 
 1.0 
 
 Per cent. 
 63.1 
 75.1 
 
 Per cent. 
 1.1 
 
 Flour 
 
 .5 
 
 
 
 1 U. S. Dept. Agr. , Office of Experiment Stations Bui. 28 (rev. ed. ) . 
 
 The increase of water in the bread hardly needs explanation, since 
 it is evidently due to the water added in making the dough. The use 
 of butter or lard and salt probably accounts for the excess of fat and 
 
29 
 
 ash. The protein and carbohydrates lost doubtless went to nourish 
 the yeast. Most of the carbon dioxid into which they were converted 
 passed out of the bread. According to Birnbaum" the baked bread 
 contains an average of 0.314 per cent of alcohol,^ by no means all of 
 that generated by the yeast (about 1 per cent, according to Snyder); 
 part is evaporated and part is probably changed into acetic acid. The 
 bacteria and other microscopic plants which accompanied the yeast 
 doubtless took their share of the protein and carbohydrates, returning 
 a part in the form of the characteristic acids and other bodies which 
 they produce. Part of the starch in the crust has been changed into 
 dextrin, and that in the crumb has become gelatinous or partly soluble. 
 The gluten, as we have seen, has taken definite shape. This really 
 means that it has coagulated very much as the white of an egg does in 
 boiling. 
 
 STALE BREAD. 
 
 Good fresh bread has a crisp crust which breaks with a snap, and an 
 elastic crumb which springs back into shape after being pressed with 
 the finger. Before bread is a day old, however, its texture has changed ; 
 its crust has become softer and tougher, while the inside seems dry and 
 crumbly, the bread is "growing stale," as we say. This was formerly 
 supposed to be due simply to the drying of the bread, but as the loss 
 of water is found by experiment to be comparatively slight, some other 
 explanation is necessary. Various explanations have been offered, of 
 which the most interesting seems that given by Boutroux in the work 
 already quoted. He maintains that the apparent dryness is due to a 
 shifting of the moisture from the crumb to the crust. When first taken 
 from the oven the dry crust cools quickly, but the moist crumb retains 
 its heat much longer. As gradually, however, its temperature falls tcj 
 that of the surrounding atmosphere, its moisture tends to distill out- 
 ward, leaving a comparatively dry crumb and moist crust. Common 
 experience shows that if stale bread is put into the oven for a few 
 minutes it regains something of its fresh consistency — a crisp crust 
 and moist crumb. This fact would be explained by the reverse of 
 Professor Boutroux's proposition; that is, the moisture is driven back 
 into the crumb. Such warmed-over bread lacks the elasticity of the 
 fresh loaf, and its interior crumbles as easily as before it was reheated. 
 This is supposed to be because the starch has undergone a chemical 
 change, the nature of which is not yet clearly understood. Indeed, 
 the whole question of staleness is one about which little has been abso- 
 lutely proved. 
 
 'Das Brotbacken. Braunschweig, 1878, p. 252. 
 
 ' On the other hand, Snyder found that no appreciable amount of alcohol remained 
 in breads after baking. (U. S. Dept. Agr., Office of Experiment Stations Bui. 67, 
 p. 16.) 
 
30 
 IMPERFECTIONS AND IMPURITIES IN BREAD. 
 
 One of the most common and dangerous faults in bread is heaviness 
 and sogginess. As we have seen, this may be caused by the use of 
 cheap flours, poor in gluten, which can not absorb all the water put 
 into the dough, or, to state it in another way, by the use of too much 
 water in proportion to the flour; by too little or by too poor yeast; 
 or by insufficient kneading, rising, or baking. Heavy bread is popu- 
 larly considered one of the most indigestible of foods. When chewed 
 it rolls itself into solid lumps, which give the saliva and gastric juices 
 very little chance to work upon them. 
 
 Occasionally the crumb of fresh bread breaks when cut, instead of 
 separating cleanly under the knife. According to Jago,' harsh dry 
 flours, not sufficiently fermented, may be the cause of this, or the 
 dough may have lost its tenacity by being overwoz'ked. 
 
 Another common fault in bread, especially in baker's bread, is a 
 crumb full of large, irregular holes instead of the small, even pores 
 which it should show. These occur in overkneaded or overraised 
 dough, or if they are found just below the crust they mean that the 
 oven was too hot and that the crust formed before the carbon dioxid 
 had finished expanding. 
 
 Sometimes bread makers are troubled by what is known as " sticky" 
 or "slimy" bread. In such cases bread three or four days old takes 
 on a light-brown color and a peculiar taste and odor. Gradually, too, 
 it becomes sticky or slimy until it may be pulled into strings, some- 
 times several feet in length. The trouble appears to be caused by the 
 common potato bacillus {Bacilhismesentericusvidgatus),a.mm\iteovga,n- 
 ism which finds its way into the materials of the dough, survives the 
 baking, and, growing in the bread, causes it to decompose. Experi- 
 ments recently made at the Wisconsin Experiment Station^ show that 
 the bacilli enter the bread with the yeast, which in the cases investi- 
 gated was a variety of the compressed yeasts ordinarily on the market. 
 It was also proved that the bacilli will survive the heat of baking. Ac- 
 cordingly, if yeasts are not carefully made such trouble may occur at 
 any time, but especially when the weather is warm and favorable to 
 the growth of the bacilli. The best safeguards are to keep the bread 
 in a cool place and to bake only as much as can be consumed within a 
 day or two. 
 
 Not infrequently, especially in damp weather, mold forms on the 
 outside, or even in the inside of bread. Mold, like yeast, is a minute 
 plant whose spores (or seeds) are floating about everywhere in the air, 
 ready to settle down and grow wherever they find a moist, suitable 
 home for themselves. The best practical way to protect bread from 
 them is to keep it in a dry, air-tight box. 
 
 ' The Science and Art of Breadmaking, by William Jago, London, 1895. 
 ^ Wisconsin Sta. Rpt. 1898, p. 110. 
 
31 
 
 But all these faults seem insignificant compared to that dread of 
 all bakers, sour bread. This is due to lactic, or, in the worst cases, 
 butyric, acid given off by undesirable bacteria in their growth. A 
 little acid is not necessarily harmful, as was seen in the discussion of 
 bread made with leaven and barm ; but when the acidity is very pro- 
 nounced or even accompanied by putrefaction (developed in company 
 with butyric acid) then something is radically wrong. Possibly the 
 vessels in which the bread was made were not thoroughly cleaned after 
 the last using and some of the undesirable bacteria got into the dough 
 from them; or perhaps the yeast contained an undue proportion of 
 these bacteria; or, if the latter were found only in normal quantities, 
 possibly the yeast itself was weak and was quickly exhausted. The 
 trouble may be due to the fact that the dough was allowed to stand 
 too long after mixing, the yeast ceased working, and the dangerous 
 bacteria which grow best in the presence of acetic acid, such as occurs 
 after alcoholic fermentation has ceased, had gotten the upper hand. 
 If none of these things are at fault, the undesirable bacteria may have 
 come from the flour itself. Such cases are fortunately very rare, and 
 if a baker guards against all the other dangers, he is pretty sure to make 
 sweet bread. If bread grows sour with age it has probably caught 
 the undesirable bacteria from the air, just as it catches mold. Very 
 rarely, however, bread perfectly sweet at first grows sour before the 
 bacteria in the air have had a chance to get at it. The only possible 
 explanation for this is that the bacteria have managed to survive the 
 baking and are growing luxuriantly in undisputed possession of the 
 good things in the bread. 
 
 Besides these acid-producing bacteria, various others occur in bread, 
 mostly harmless, but some of them very curious in their effects. Most 
 striking among these is the Micrococcus prodAgiosus, a minute organism 
 which makes blood-red spots in the dough and whose presence gave 
 rise to many interesting superstitions during the Middle Ages. 
 
 Aside from the adulterants mentioned in the section on flour, those 
 most commonly met with in bread are mineral salts mixed into the dough 
 for the purpose of producing a good-looking loaf from poor flour. 
 Alum is the most common of these. It tends to check the action of the 
 diastase and permits a weak flour to absorb more water than usual. It 
 also improves the color of the bread. Many reliable bakers use it under 
 the impression that it does good and not harm; but besides producing 
 a bread whose nutritive value is not so great as appearances indicate, 
 it is believed to be really injurious to the digestive system, and must 
 be ranked as an objectionable adulterant. Alum tests are usually made 
 by soaking a sample of the suspected bread in a solution of tincture of 
 logwood and ammonium carbonate, in which alum betrays itself by a 
 bluish color. Copper sulphate is used to produce an effect similar to 
 that of alum in bread, but is believed to be more dangerous. Lime 
 exerts practically the same influence and does no particular harm. Its 
 
32 
 
 use is reprehensible only because it gives poor bread the appearance 
 of good bread. 
 
 Soda is often used in bread to prevent souring, and as it does not 
 lessen the value can hardly be called an adulterant.. In breads made 
 from special flours poor in gluten — oatmeal, barley, etc. — soda is neces- 
 sary in the production of a sweet, well-raised loaf. 
 
 NUTRITIVE VALUE AND COST OF BREAD. 
 
 COMPARISON OF THE COMPOSITION OF BKEADS AND OTHER 
 
 FOODS. 
 
 If we wish to know which of several foods furnishes the most actual 
 nourishment for the least cost, we must know not only the actual price 
 and the nutritive ingredients of each, but also their relative digesti- 
 bility, and the one which is found to furnish the greatest amount of 
 digestible nutrients for a given sum will be the cheapest. 
 
 To show the difl:erence in the proportions of the different food 
 ingredients in various foods, it may be well to compare the analyses of 
 bread and other foods as given in the following table: 
 
 Composition of various food materials.^ 
 
 Num- 
 ber of 
 analy- 
 ses. 
 
 Refuse. 
 
 Fat. 
 
 Carbo- 
 hydrates. 
 
 Ash. 
 
 Com bread (johnnycake) 
 
 Rye bread 
 
 Rye and wheat bread 
 
 Wheat bread, "gluten" 
 
 Wheat bread, "graham" 
 
 Wheat bread, ' ' rolls " 
 
 Wheat bread from high-grade pat- 
 ent flour 
 
 Wheat bread from regular patent 
 
 flour 
 
 Wheat bread from bakers' flour 
 
 Wheat bread from low-grade flour . . 
 Wheat bread, average, all analyses.. 
 
 Whole wheat bread 
 
 Crackers 
 
 beef, ribs; 
 
 Edible portion 
 
 As purchased 
 
 Veal, leg: 
 
 Edible portion 
 
 As purchased 
 
 Mutton, leg: 
 
 Edible portion 
 
 As purchased 
 
 Cod steaks: 
 
 Edible portion 
 
 As purchased ; .- 
 
 Hens' eggs; 
 
 Edible portion 
 
 As purchased 
 
 Butter 
 
 Milk, whole 
 
 Potatoes: 
 
 Edible portion 
 
 As purchased 
 
 Apples: 
 
 Edible portion 
 
 As purchased 
 
 Chocolate, as purchased 
 
 198 
 12 
 71 
 
 60 
 
 16.8 
 "ii."7' 
 'iY.7 
 ' '9.2 
 
 'ii."2' 
 
 20.0 
 
 '25.'6' 
 
 Pa- ct. 
 38.9 
 36.7 
 35.3 
 38.2 
 35.7 
 29.2 
 
 32.9 
 
 34.1 
 39.1 
 40.7 
 36.3 
 38.4 
 6.8 
 
 55.5 
 39 6 
 
 71.7 
 63.4 
 
 63.2 
 51.9 
 
 79.7 
 72.4 
 
 73.7 
 66.5 
 11,0 
 87.0 
 
 78.3 
 62.6 
 
 84.6 
 63.3 
 5.9 
 
 Per ct. 
 7.9 
 9.0 
 11.9 
 9.3 
 8.9 
 8.9 
 
 8.7 
 
 9.0 
 10.6 
 12.6 
 9.2 
 9 7 
 10,7 
 
 17.5 
 12.7 
 
 20.7 
 18.3 
 
 18.7 
 15.4 
 
 18.7 
 17.0 
 
 13.4 
 11.9 
 1.0 
 3.3 
 
 2.2 
 1.8 
 
 Per ct. 
 4.7 
 .6 
 .3 
 1.4 
 1.8 
 4.1 
 
 1.3 
 
 1.2 
 I.l 
 1.3 
 .9 
 8 8 
 
 26.6 
 30.6 
 
 6.7 
 5.8 
 
 17.5 
 14.5 
 
 .5 
 .5 
 
 10.6 
 9.3 
 
 85.0 
 4.0 
 
 .5 
 
 .3 
 
 48.7 
 
 Pe?- a. 
 46.3 
 53.2 
 51.5 
 49.8 
 52.1 
 56.7 
 
 56.5 
 
 54.9 
 48.3 
 44.3 
 53.1 
 49.7 
 71.9 
 
 5.0 
 
 18.4 
 14.7 
 
 14.2 
 10.8 
 30.3 
 
 Per a. 
 2.2 
 1.6 
 1.0 
 1.3 
 1.6 
 1.1 
 
 1.3 
 J.l 
 
 1.3 
 1.8 
 
 .6 
 
 1.1 
 1.0 
 
 1.0 
 .8 
 
 1.2 
 1.0 
 
 1.0 
 
 .9 
 
 3.0 
 
 .7 
 
 1.0 
 
 .8 
 
 .3 
 
 .3 
 
 2.2 
 
 1 U. S. Dept. Agr., Office of Experiment Stations Bui. 28 (rev. ed.) 
 
33 
 
 From various dietary standards it is reckoned that the average man 
 at moderate work requires about 0.28 lb. of protein to 0.28 lb. of fat 
 and 0.99 lb. of carbohydrates in his daily food, which together furnish 
 3,500 calories of energy. The harder he works the more food he 
 will need. Milk contains the three classes of nutrients, but not in 
 the proper proportion for adults in health. The large quantities of 
 milk which a man would have to drink in order to obtain the necessary 
 amount of nourishment make it inconvenient for exclusive use. Meats 
 are rich in protein. Vegetables are especially rich in carbohydrates. 
 Bread contains the three classes of nutrients in about the right propor- 
 tion; still in order to get the requisite amount of protein from it one 
 would have to take more carbohydrates than is otherwise necessary. 
 It must not be supposed that it is impossible to live without the three 
 classes of foods in the given proportion. The poor of India and China 
 and other Eastern countries often live almost entirely on cereals, and 
 have become so accustomed to this diet that they refuse to change. 
 They, however, secure more protein than is ordinarily supposed by the 
 use of sauces, vegetable cheese, etc., made from legumes, notably soy 
 beans. ^ 
 
 Turning to the bread analyses, we see that wheat bread from low- 
 grade flour, wheat bread from bakers' flour, and rye-and- wheat bread 
 contain the largest amount of protein; corn bread and wheat rolls, the 
 most fat; and wheat rolls, wheat bread from high-grade patent flour, 
 and wheat bread from regular patent flour, the most carbohydrates. 
 The amount of fat would, of course, vary greatly with the amount of 
 shortening added in making the bread, and the examination of a large 
 number of analyses of the same kind of bread has shown that the 
 amount of each of the several nutrients varies in the same sort of bread 
 within rather wide limits. Judged by their composition, all breads 
 are nutritious foods, and too great stress should not be laid on the 
 variations in composition between the different kinds. 
 
 DIGESTIBILITY OF DIFFERENT KINDS OF BREAD. 
 
 The next question is. Which kind of bread furnishes the greatest 
 amount of digestible nutrients? Unfortunately no experiments have 
 been made with exactly the same materials as those represented in 
 these tables, but investigations conducted on similar lines will not be 
 without value in this connection. 
 
 Among the best known of such experiments are those conducted by 
 Meyer and Voit, of Munich, about twenty-five years ago. Four kinds 
 of bread were used: (1) Rye bread, raised with a leavening powder; 
 (2) bread made from a mixture of rye and wheat flours and raised with 
 yeast; (3) fine white bread raised with yeast, and (4) coarse whole- 
 
 ' U. S. Dept. Agr., Farmers' Bui. 58, Appendix. 
 16010— No. 112 3 
 
34 
 
 wheat bread, which the Germans call "pumpernickel," raised with 
 yeast. The third of these, fine white bread, yielded the highest per- 
 centage of digestible nutrients, next came the wheat and rye bread, then 
 the bread raised with the leavening powder, and last the pumpernickel. 
 The pumpernickel may be left out of account, as it was too coarse 
 to be justly compared with whole-wheat bread such as is made in the 
 United States. The fine white bread was the lightest of the other three, 
 next to it stood the rye and wheat, and last that raised with the pow- 
 der, the same order that they took with regard to digestibility. These 
 experiments prove, not so much the comparative value of different 
 flours, as that the digestibility of bread depends largel}'^ upon its light- 
 ness. 
 
 Recent investigations conducted at the Maine Experiment Station' 
 throw light on the question of comparative value of various kinds 
 of bread. Experiments were carried on with several subjects with 
 the following results: 
 
 Comparison of nulrienU digested and energy utilized in different kinds of bread. ' 
 
 
 Number 
 of experi- 
 ments. 
 
 Nutrients digested. 
 
 Energy 
 utilized. 
 
 Kind of food. 
 
 Protein. 
 
 -Fat. 
 
 Carbo- 
 hydrates. 
 
 White bread alone 
 
 4 
 9 
 6 
 5 
 
 Per cent. 
 82 
 88.3 
 77 
 86.6 
 
 Per cent. 
 70.7 
 66.6 
 68.1 
 46.2 
 
 Per cent. 
 98.4 
 98.2 
 92.4 
 97.2 
 
 Per cent. 
 92 2 
 
 White bread with milli 
 
 94 8 
 
 
 
 EIntire-wheat bread with milk 
 
 94 
 
 
 
 1 Maine Sta. Rpt. 1898, p. 207. 
 
 The figures in the last column, marked "energy utilized," were 
 found by burning (in a bomb calorimeter) the equivalent of the food 
 consumed and measuring the heat given off thereby, and from this cal- 
 culating the heat which the amount digested should furnish. Heat and 
 the energy of muscular work, voluntary and involuntary, are but dif- 
 ferent manifestations of the same force; consequently, using the proper 
 factors, we may approximately determine the value of any food as a 
 source of energy by measuring its heat of combustion. 
 
 From this table we infer that white bread yields the highest percent- 
 age of digestible nutrients; next comes entire wheat and last graham 
 bread. (It should be stated that the graham bread used here was not 
 the unleavened variety, but was made with yeast.) As was to be 
 expected the whole-wheat breads made from carefully prepared flours 
 proved much more digestible than the cheap pumpernickel used in the 
 German experiments. It is also worth noticing that the entire wheat 
 flour prepared without the three outer layers of the grain makes a more 
 digestible bread than the graham flour containing the whole grain. 
 
 1 Maine Sta. Rpt. 1898, p. 197. 
 
35 
 
 Part of the experiments reported in this table were made with 
 bread alone; the rest with bread and milk. This was because a man 
 accustomed to a varied diet finds it impossible to digest or even to eat 
 large quantities of bread alone. How much more nourishment he 
 gains from the same amount of bread taken with milk may be seen by 
 comparing the experiments with white bread alone with those with 
 white bread and milk. In the Munich experiments the subject took 
 beer and butter with his bread. In both cases the figures quoted were 
 calculated to give the nutrients of the bread alone. 
 
 The amount of actual nourishment which a given weight of bread 
 will furnish is found by multiplying the weights of its nutritive ingre- 
 dients by their percentages of digestibility. Let us take the number 
 of heat units or calories^ which a gram of bread will give off when 
 burned as the measure of its nutritive ingredients. From the tables 
 given in the Maine Station Report these are found to average: 
 
 Calories per 
 gram. 
 
 White bread 2. 83 
 
 Graham bread _ 2. 55 
 
 Entire-wheat bread 2. 65 
 
 Multiplying these by the percentage of energy utilized from each 
 bread, we find that 1 gram of white bread eaten alone yielded 2.69 
 calories, eaten with milk, 2.78 calories; 1 gram of graham bread yielded 
 2.18 calories and 1 gram of entire-wheat bread 2.35 calories. From 
 this point of view white bread is still the most advantageous. The 
 chief argument for the entire wheat and graham flours is that they 
 furnish larger amounts of protein, the kind of food in which bread is 
 most lacking. Let us see what these Maine experiments say of this. 
 From them we calculate that 1 gram of average white bread contains 
 0.086 gram of protein, graham bread 0.083 gram, and entire-wheat 
 bread 0.086 gram. Multiplying these by the percentages of digesti- 
 bility of protein, 1 gram of white bread with milk will furnish 0.076 
 gram of digestible protein, while the same weights of graham and 
 entire-wheat bread wiU furnish, respectively, 0.064 and 0.074 gram. 
 Thus we see that even in regard to the amount of protein digested, 
 white bread is still the most valuable; next comes entire wheat and 
 last graham bread. 
 
 As regards the claim that the bran-containing flours f ui-nish valuable 
 mineral matters and fats, it should be stated that as yet no experiments 
 have been made to test the digestibility of these substances, and until 
 that is done nothing positive can be said on either side. Too much 
 stress should not be laid on the importance of the extra amount of 
 phosphates and other ash constituents of bran. Fine flour also con- 
 tains these same constituents and it is not unlikely that they are more 
 
 'A calorie represents the amount of heat necessary to raise a kilogram of water 
 1° C, or a pound of water 4° F. 
 
36 
 
 available than in the bran, even if finely ground. These substances 
 are of undoubted value, but there is little experimental data to show 
 the amount of different ash constituents necessary for maintaining the 
 body in health. It is doubtless safe to say that the ordinary mixed 
 diet of children and adults furnishes an abundance of mineral matter. 
 The coarser flours, with the particles of bran, often increase the peri- 
 staltic action of the intestine and thus tend to prevent constipation. 
 They may at times otherwise aid digestion, hence for persons in need 
 of a laxative, bread made from such flours may often be preferable 
 to white flour, but for a healthy person its claim of superior value 
 is very questionable. Certainly no plea can be made for them on the 
 ground of economy, for entire-wheat and graham flours cost more than 
 white flour. 
 
 The coarse flour used in the German bread called pumpernickel 
 costs less, but it is doubtful whether a cent's worth of it furnishes as 
 much nourishment as a cent's worth of white flour. The comparative 
 digestibility of the various grades of white flour was recently investi- 
 gated in Minnesota^ and it was found that the difference between the 
 amounts of digestible nutrients furnished by breads made from patent 
 roller process and bakers' flours was very slight. Unfortunately 
 there are no statistics at hand from which to compute the comparative 
 cost of the digestible nutrients in r3'e, corn, and other breads. In 
 German investigations recently made in reference to army bread ^ the 
 conclusions are drawn that if complete digestion of the nutrients of 
 the bread is the main object the cheaper grades of white flour are the 
 most economical, but that if low cost is also an object, a mixture of 
 rye and white flour is to be recommended. 
 
 Statements of a popular nature are frequently met with on the 
 unwholesomeness of hot bread. The fact that bread is hot has doubt- 
 less little to do with the matter. New bread, especially that from a 
 large loaf, may be readily compressed into more or less solid masses, 
 and it is possible that such bread would be much less finelj'' masticated 
 than crumblj^, stale bread, and that, therefore, it might offer more 
 resistance to the digestive juices of the stomach. However, when such 
 hot bread as rolls, biscuit, or other form in which the crust is very 
 large in proportion to the crumb is eaten this objection has much less 
 force. There is little diificulty in masticating the crust, and it is doubt- 
 less usually finely divided. 
 
 MARKET VAIiITE OF BREAD. 
 
 When we come to the actual market price of bread we find that it 
 bears little relation to the nutritive ingredients or even to the cost of the 
 materials. Experiments made at New Brunswick, N. J., and Pittsburg, 
 
 1 U. S. Dept. Agr., Office of Experiment Stations Bui. 67, p. 34. 
 ^Experiment Station Record, 10, p. 375. 
 
37 
 
 Pa./ tend to show that bakers in those sections set their prices by the 
 size and trade name of the bread. Thus in New Brunswicls, where tifty 
 analyses were made, the bread containing the highest amount of nutri- 
 ents and that containing the lowest were sold at exactly the same price 
 per pound, 4.1 cents. In New Jersey it appeared that the larger the 
 loaf the higher the cost per pound tended to rise. The average cost 
 of bread seems to vary in different localities; thus, while the investi- 
 gations just referred to were being carried on it averaged from 5 to 
 6 cents a pound in Middletown, Conn., from 3.8 to 4.9 in different 
 cities in New Jersey, and 3.76 in Pittsburg. 
 
 When the selling price of bread and the cost of its ingredients are 
 compared the results are still more striking. In two experiments 
 made in New Jersey it was found that two lots of bread made from 
 materials costing, respectively, $2.28 and $2.56 were sold for $5.86 and 
 f6.08. This represents a profit of 116.5 per cent over the cost of the 
 materials, or, to put it in dollars and cents, the baker received $216. 50 
 for bread whose materials cost him $100. In Pittsburg the average 
 increase in price over the original cost was 110 per cent. Even sub- 
 tracting from this the cost of labor, rent, fuel, etc. , the profits of the 
 baker are so high that, to quote from the Pittsburg report, "It would 
 seem that in the case of very poor families * * * an important 
 pecuniary saving would result if bread was made at home. To the 
 man in ordinary circumstances it must always be more a question of 
 convenience and taste than of cost. In short, each famil}' can best 
 determine for itself whether it is desirable to pay the baker for the 
 trouble of making the bread and delivering it, or whether the labor of 
 making and the extra fuel for baking can best be provided at home." 
 
 SUMMARY. 
 
 Cereals of some kind or other have always made an important item 
 of human food, and of all the forms in which they have been used 
 bread has proved the most satisfactory, because the most digestible 
 and appetizing, To prepare the grain for bread making it is usually 
 cleansed, crushed, and sifted into a fine, soft powder which we call 
 flour. Among various flours the preference should of course be given 
 to the one which yields the most nutritious loaf for the least money. 
 
 The nutritive value of bread depends not only on its chemical com- 
 position, but also on its digestibility, and digestibility, in its turn, 
 seems to depend largely on the lightness of the loaf. It iS the gluten 
 in a flour which gives it the power of stretching and rising as the gas 
 from the yeast expands within it, and hence of making a light loaf. 
 Eye, barley, and oats have less gluten than wheat, and maize has 
 none, and therefore wheat, despite its higher cost, yields the most 
 
 'U. S. Dept. Agr., Office of Experiment Stations Buls. 35 and 52. 
 
38 
 
 nutriment for a given sum. It is possible that of the various kinds of 
 wheat flour those containing part of the bran — entire wheat and graham 
 flours — furnish the body with more mineral matters than fine white 
 flour, but they probably do not yield more digestible protein, as was 
 for a time supposed. It seems safe to say that, as far as we yet 
 know, for a given amount of money white flour yields the most actual 
 nourishment with the various food ingredients in the best proportion. 
 
 The raising or leavening of bread is usually brought about by letting 
 yeast develop in it. These minute plants feed upon sugar in the 
 dough and in their growth give off alcohol and carbon dioxid gas, 
 which latter, expanding with the heat, forces its way through the dough 
 and thus lightens it. In order to give the yeast a better chance to 
 work, the dough is usually "set to rise" for some hours before it is put 
 into the oven. There are many methods of growing yeast at home or 
 in the bakery, but the compressed yeasts now in the market seem to 
 give equally good results with so much less labor that their use, in the 
 United States at least, is becoming practically universal. 
 
 The lightness and sweetness of bread depend as much on the way 
 in which it is made as on the materials used. The gx-eatest care should 
 be used in preparing and baking the dough and in cooking and keep- 
 ing the finished bread. Heavy, badly raised bread is a very dangerous 
 food, and unfortunately very common, and probably more indigestion 
 has been caused by it than by all other badly cooked foods. 
 
 As compared with most meats and vegetables, bread has practically 
 no waste and is very completely digested. It is too poor in protein to 
 be fittingly used alone, but when used with due quantities of other 
 foods it is invaluable, and well deserves its title of "the staff of life." 
 
39 
 
 FARMERS' BULLETINS. 
 
 The following is a list of the Farmers' Bulletins available for distribution, showing 
 the number, title, and size in pages of each. Copies will be sent to any address 
 on application to Senators, Representatives, and Delegates in Congress, or to the Secre- 
 tary of Agriculture, Washington, D. C. The missing numbers have been discon- 
 tinued, being superseded by later bulletins. 
 
 16. 
 21. 
 
 22. 
 24. 
 25. 
 27. 
 28. 
 29. 
 30. 
 31. 
 32. 
 33. 
 34. 
 35. 
 36. 
 
 39. 
 40. 
 42. 
 43. 
 44. 
 45. 
 46. 
 47. 
 48. 
 49. 
 60. 
 51. 
 52. 
 53. 
 54. 
 55. 
 56. 
 57. 
 58. 
 59. 
 60. 
 01. 
 62. 
 63. 
 64. 
 65. 
 66. 
 67. 
 68. 
 69. 
 70. 
 71. 
 72. 
 73. 
 74. 
 75. 
 76. 
 77. 
 78. 
 79. 
 80. 
 81. 
 82. 
 83. 
 S4. 
 85. 
 86. 
 87. 
 
 Leguminous Plants. Pp. 24. 
 
 Barnyard Manure. Pp. 32. 
 
 The Feeding oJ Farm Animals. Pp. 32. 
 
 Hog Cholera and Swine Plague. Pp. 16. 
 
 Peanuts: Culture and Uses. Pp. 24. 
 
 Flax for Seed and Fiber. Pp. 16. 
 
 Weeds: And How to Kill Them. Pp. 32. 
 
 Souring and Other Changes In Milk. Pp. 23. 
 
 Grape Diseases on the Pacific Coast. Pp. 15. 
 
 Alfalfa, or Lucern. Pp. 24. 
 
 Silos and Silage. Pp. 32. 
 
 Peach Growing for Market. Pp. 24. 
 
 Meats: Composition and Cooking. Pp. 29. 
 
 Potato Culture. Pp. 24. 
 
 Cotton Seed and Its Products. Pp. 16. 
 
 Kafir Corn: Culture and Uses. Pp.12. 
 
 Spraving for Fruit Diseases. Pp. 12. 
 
 Onion Culture. Pp. 31. 
 
 Farm Drainage. Pp. 24. 
 
 Facts About Milk. Pp.29. 
 
 Sewage Disposal on the Farm. Pp. 20. 
 
 Commercial Fertilizers. Pp. 24. 
 
 Insects Injurious to Stored Grain, Pp.24. 
 
 Irrigation in Humid Climates. Pp. 27. 
 
 Insects Affecting the Cotton Plant. Pp. 32. 
 
 The Manuring of Cotton. Pp. 16. 
 
 Sheep Feeding. Pp. 24. 
 
 Sorgnum as a Forage Crop. Pp. 20. 
 
 Standard Varieties of Chickens. Pp. 48 
 
 The Sugar Beet. Pp. 48. 
 
 How to Grow JIushrooms. Pp. 20. 
 
 Some Common Birds. Pp. 40. 
 
 The Dairy Herd. Pp. 24. 
 
 Experiment Station Work— I. Pp. 31 . 
 
 Butter Making on the Farm. Pp. 16. 
 
 The Soy Bean as a Forage Crop. i'p. 24. 
 
 Bee Keeping. Pp. 32. 
 
 Methods of Curing Tobacco. Pp. 16. 
 
 Asparagus Culture. Pp. 40. 
 
 Marketing Farm Produce. Pp. 28. 
 
 Care of Milk on the Farm. Pp. 40. 
 
 Ducks and Geese. Pp. 48. 
 
 Experiment Station Work— II. 
 
 Meadows and Pastures. Pp. 28. 
 
 Forestry for Farmers. Pp. 48. 
 
 The Black Kot of the Cabbage. 
 
 Experiment Station Work — III. 
 
 Insect Enemies of the Grape. Pp. 23. 
 
 Essentials in Beef Production. Pp. 24. 
 
 Cattle Ranges of the Southwest. J"p. 32. 
 
 Experiment Station Work — IV. 
 
 Milk as Food. Pp. 39. 
 
 The Grain Smuts. Pp. 20. 
 
 Tomato Growing. Pp. 30. 
 
 The Liming of Soils. Pp. 19. 
 
 Experiment Station Work — V. 
 
 Experiment Station Work— VI. 
 
 The Peach Twig-borer. Pp. 16. 
 
 Corn Culture in the South. Pp. 24. 
 
 The Culture of Tobacco. Pp. 24. 
 
 Tobacco Soils. Pp. 23. 
 
 Experiment Station Work- VII. 
 
 Fish as Food. Pp.30. 
 
 Thirty Poisonous Plants. Pp. 32. 
 
 Experiment Station Work— VIII. 
 
 Alkali Lands. Pp. 23. 
 
 Cowpeas. Pp.16. 
 
 Potato Diseases and Treatment. 
 
 Experiment Station Work— IX. 
 
 Sugar as Food. Pp. 27. 
 
 The Vegetable Garden . Pp. 24. 
 
 Good Roads for Farmers. Pp. 47. 
 
 Raising Sheep for Mutton. Pp. 48. 
 
 Pp.32. 
 
 Pp. 22. 
 Pp. 32. 
 
 Pp. 32. 
 
 Pp. 32. 
 Pp.28. 
 
 Pp. 32. 
 
 Pp. 32. 
 
 Pp. 12. 
 Pp. 30. 
 
 97. 
 
 100. 
 101. 
 102. 
 103. 
 104. 
 105. 
 106. 
 107. 
 108. 
 109. 
 110. 
 111. 
 112. 
 113. 
 114. 
 116. 
 116. 
 117. 
 
 118. 
 119. 
 120. 
 121. 
 
 122. 
 123. 
 
 124. 
 125. 
 
 Experiment Station Work — X. Pp. 82. 
 
 Suggestions to Southern Farmers.' Pp. 48. 
 
 Insect Enemies of Shade Trees. Pp. 30. 
 
 Hog Raising in the South. Pp. 40. 
 
 Millets. Pp. 28. 
 
 Southern Forage Plants. Pp. 48. 
 
 Experiment Station Work— XI. Pp. 32. 
 
 Notes on Frost. Pp. 24. 
 
 Experiment Station "\\'ork— XII. Pp. 32. 
 
 Breeds of Dairy Cattle. Pp. 48. 
 
 Experiment Station Work— XIII. Pp. 32 
 
 Saltbushes. Pp. 20. 
 
 Farmers' Reading Courses. Pp. 20. 
 
 Kice Culture in the United States. Pp. 28. 
 
 Farmers' Interest in Good Seed. Pp. 24. 
 
 Bread and Bread Making. Pp. 39. 
 
 The Apple and How to Grow It. Pp. 32. 
 
 Experiment Station Work— XIV. Pp. 28. 
 
 Hop Culture in California. Pp. 27. 
 
 Irrigation in Fruit Growing. Pp. 48. 
 
 Sheep, Hogs, and Horses in the Northwest. 
 
 Pp.28. 
 Grape Growing in the South. Pp. 32. 
 Experiment Station Work— XV. Pp. 31. 
 Insects Affecting Tobacco. Pp. 32. 
 Beans, Peas, and other Legumes as Food. 
 
 Pp. 32. 
 Experiment Station Work— XVI. Pp. 32. 
 Red Clover Seed: Information for Pur- 
 chasers. Pp. 11. 
 Experiment Station Work— XVII. Pp. 32. 
 
 Protection of Food Products from Injurious 
 'Temperatures. Pp. 26. 
 
 Practical Suggestions for Farm Buildings. 
 Pp.48. 
 
 Important Insecticides. Pp. 42. 
 
 Eggs and their Uses as Food. Pp. 32. 
 
 Sweet Potatoes. Pp. 40. 
 
 The Mexican Cotton Boll Weevil. Pp. 30. 
 
 Household Test for Detection of Oleomar- 
 garine and Renovated Butter. Pp. 11. 
 
 Insect Enemies of Growing Wheat. Pp. 40. 
 
 Experiment Station Work- XVIII. Pp. 32. 
 
 Tree Planting in Rural School Grounds. 
 Pp. 38. 
 
 Sorghum Sirup Manufacture. Pp. 40. 
 
 Earth Roads. Pp. 24. 
 
 The Angora Goat. Pp. 48. 
 
 Irrigation in Field and Garden. Pp. 40. 
 
 Emmer; A Grain for the Semiarid Regions. 
 Pp. 16. 
 
 Pineapple Growing. Pp. 48. 
 
 Poultry Raising on the Farm. Pp. 16. 
 
 The Nutritive and Economic Value of Pood. 
 Pp. 48. 
 
 The Conformation of Beef and Dairy Cattle. 
 Pp. 44. 
 
 Experiment Station Work— XIX. Pp.32. 
 
 Carbon Bisulphid as an Insecticide. Pp. 28. 
 
 Insecticides and Fungicides. Pp. 16. 
 
 Winter Forage Crops for the South. Pp. 36. 
 
 Celery Culture. Pp. 32. 
 
 Experiment Station Work— XX. Pp. 32. 
 
 Clearing New Land. Pp. 24. 
 
 Dairying in the South. Pp. 48. 
 
 Scabies m Cattle. Pp. 24. 
 
 Orchard Enemies in the Pacific Northwest. 
 Pp. 39. 
 
 The Home Fruit Garden: Preparation and 
 Care. Pp. 20. 
 
 How Insects Affect Health in Rural Districts. 
 Pp. 20. 
 
 o