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ing and aeration, the fermentation process is changed from anaerobic to aerobic form, which appears necessary in order that the full development and complete workings of the yeast cells can take place.

The principal chemical changes which take place in bread making are: (1) production of carbon dioxide and alcohol; (2) change of insoluble carbohydrates to soluble form; (3) production of lactic and other acids; (4) formation of volatile hydrocarbon derivatives; (5) change of solubility and molecular structure of the proteid compounds; (6) formation of amide and ammonium compounds from proteids; and (7) partial oxidation of the fat. The agents which bring about these chemical changes are ferments and heat. The yeast plant, as previously stated, secretes a number of enzymes or chemical products which are active agents in producing chemical changes. Diastase and invertase act upon the carbohydrates forming dextrose sugars which undergo alcoholic fermentation. This results in the production of about one per cent each of carbon dioxide and alcohol. During the process of baking, nearly all of the alcohol is expelled, as only traces of alcohol have been obtained in fresh bread. The joint action of the yeast and heat upon the starch granules results in changing about 6 per cent of the starch to soluble forms as dextrin and dextrose sugars. Some of the starch grains are ruptured, others are partially disintegrated by the ferment action, while many appear to be unaltered. These physical changes of the starch granules render bread more susceptible to the action of the digestive fluids.

Lactic, acetic, and occasionally butyric and other acids are formed during bread making, particularly if the alcoholic ferment becomes inactive and sour dough is formed. From .3 to .4 per cent of acid, calculated as lactic acid, is formed and unites with the gluten proteids during the baking process. The amount of volatile hydrocarbon derivatives formed during bread making is small, less than 10 of a per cent. These compounds give the characteristic aroma to freshly baked bread.

The wheat proteids undergo a number of chemical changes during bread making. (See WHEAT; WHEAT FLOUR.) While the proteids of wheat are mainly in the form of insoluble glutens, small amounts are present as albumin and globulin. Wheat gluten is composed of two substances: gliadin, a glue-like body, and glutenin, a gray powder to which the bands of gliadin adhere. Gliadin constitutes the binding material of the flour, and enables the dough to retain the carbon dioxid gas formed during fermentation and this leavens the bread. An excessive amount of gliadin produces a soft sticky dough, while an excess of glutenin reduces the power of expansion of the dough. In hard wheat flours, the gluten is composed of about 35 per cent glutenin and 65 per cent gliadin. The ratio of gliadin to glutenin determines very largely the quality of the bread. The removal of the gliadin proteid from flour results in a loss of bread-making properties, as the dough fails to expand. Any interference with the gliadin-glutenin ratio in flour affects its bread-making qualities.

Yeast is employed in bread making, not only to produce gas and expand the dough, but also

to produce other chemical changes as formation of acid bodies that combine with the proteids to form acid proteids which frequently favorably affect the gliadin-glutenin ratio. Because of the difference in the amounts of gliadin and glutenin in flours, the methods of bread making must be varied to meet the requirements of different kinds of flour.

In average bread making, from 12 to 2 per cent of dry matter is lost by fermentation and the formation of volatile products as carbon dioxid, alcohol, volatile hydrocarbons, and ammonium products. The losses fall alike upon both the carbohydrates and proteids. With prolonged fermentation, the losses of dry matter may amount to 5 per cent or more.

Bread varies in chemical composition according to the quality of the flour from which it is made. Some flours contain 12 per cent and more of proteids, while others contain 8 per cent and less, according to the composition of the wheat from which the flour has been milled. (See WHEAT.) Flours of high protein content contain proportionally less starch than low protein flours. The starch and protein content of flour and bread vary inversely.

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Straight (white flour). 11.99 1.61 75.36
Entire-wheat flour.. 12.26 2.24 73.67
Graham flour..
12.65 2.44 74.58

Per cent


1.28 .88

When either whole or skim milk is used, the bread contains more protein. The use of milk in bread making is desirable because of its increasing the nutritive value of the bread product. The amount of fat in bread varies with the amount of lard, butter, or other form of shortening used in the making. Occasionally a large amount of lard is used to prevent the bread from drying out too rapidly.

The composition of bread is influenced also by the method of milling the wheat. The outer and aleurone layers of the wheat kernel contain more nitrogen, fat, and ash than the floury portion, hence their addition, as in graham and entire-wheat flours causes the bread to be richer in these compounds. When milled from the same lot of wheat, graham, entirewheat, and white flours have the following composition:

.50 1.02 1.72

Digestion experiments have shown that the finer grades of white flour are more digestible than either graham or entire-wheat flour; the

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Protein Per Cent


9.9 9.8


The higher degree of digestibility of the white bread results in its furnishing a larger amount of available nutrients to the body than is supplied by either graham or entire-wheat. The available nutrients in the three kinds of flour milled from the same lot of wheat are as follows:




Carbohydrates Per Cent








Calories Per gram

3.650 3-445 3-350

White bread when properly made from a glutinous flour has a high degree of digestibility, and with the exception of some of the oat preparations supplies the body with more available nutrients than is secured from any other cereal.

Bread is not generally subject to adulteration, although various forms of sophistication have been practised. The most common form of adulteration is the use of a small amount of alum with damaged and inferior grades of flour. Occasionally rye bread is in part prepared from wheat flour. Wheat bread also has been prepared from flour of mixed cereals, as corn and wheat. During recent years this practice has practically ceased in the United States owing to national laws regulating the taxing and branding of wheat flours when mixed with other cereals or materials.

During the process of baking, the temperature of the oven may range from 225° to 260° C.; the interior of the loaf, however, does not reach 100° C. Various forms of ovens, heated in different ways and with different kinds of fuel are in use. Modern bake ovens are usually so constructed as to secure the highest efficiency from the fuel consumed and to prevent unnecessary losses of heat by radiation. Some ovens are provided with self-registering thermometers and thermostats for the regulation of the temperature, also devices as trucks, racks, and trays for receiving the bread. The bake-ovens in use in different countries vary widely in form and method of heating. Before stoves were used, bread was baked in special ovens usually adjacent to open fireplaces. In some localities, brick bake-ovens were built out of doors. A fire was made in the oven and when the bricks were sufficiently heated, the coals were removed and the unbaked bread was placed in the hot oven, where it readily baked. This plan of heating ovens is even now in use in some European countries. For home bread-making purposes in the United States stoves provided with bake-ovens are used almost exclusively.

Bread, as offered in the market, is made in loaves of various forms, which usually weigh about one pound. In some countries laws regulating the weight of the bread are rigidly enforced, and bakeries are subject to sanitary inspection. During the process of doughing, flour will absorb from 40 to 60 per cent of water. During the baking process a part of this water is expelled as steam. On account of the additional water absorbed, a pound loaf of bread can be made from .65 to 75 pounds of flour. A barrel of flour weighing 196 pounds will make from 275 to 300 pound loaves of bread, which will contain about 170 pounds of dry material. Since bread readily loses water, allowance is usually made in baking for subsequent shrinkage in weight. Because of greater power for absorption of water, some flours are more valuable for bread-making purposes than are others. The larger the amount of gluten which a flour contains, the greater is the power to absorb water and to produce a large number of loaves per barrel. A low gluten content influences the moisture content of bread more than it does the size of the loaf. Flour which contains a well-balanced gluten can have 10 or even 20 per cent of starch or other material added without influencing the size of the loaf, and on the other hand, the addition of moist gluten to dough does not materially increase the power of expansion or the size of the loaf. Flours which possess poor qualities of expansion are often improved by blending with those of different character. In many larger bakeries, special machinery has been devised for the blending of different qualities of flour. In some bakeries, one kind of flour is used for making the sponge which is then mixed with another kind in making the dough. Some of the more expensive and higher grades of flour are often used in this way to impart quality to the bread product. Comparative baking trials are made when flours are tested for technical purposes, the same weight of flour, yeast, water, and other materials being used. From the tests the physical properties of the bread are determined, as color, size of loaf, weight, odor, and taste.

Special trade names are given to different kinds of bread. In some bakeries, a bread known as home-made or domestic bread is made. Different kinds of bread are usually due to differences in manipulation, as extent of fermentation, kneading, lightness of dough, etc. For domestic purposes, a moist loaf of good quality is usually preferred to one that is extremely porous and readily dries. Different names are applied to various bread products, as Vienna bread, a high-grade white bread made with yeast, milk, shortening, salt, and in some instances a small amount of sugar. Various other ingredients are sometimes used in bread making, as potatoes, potato starch, potato water, barley water, buttermilk, molasses, etc. These materials take only a secondary part in the process, influencing the taste and flavor more than the composition, unless used in large amounts. The flavor of bread is due to the small amount of ethereal products formed during fermentation by the action of the ferments in the yeast and the soluble ferments or enzymes in the flour. Undesirable as well as the desirable flavoring products are developed during the process of fermentation in case the yeast is of poor quality or the flour is unsound.


There are many different kinds of bread made from the different cereals, as pumpernickel, which is made from the graham of rye, flat bread made in large flat cakes without yeast from wheat flour, and baked on the top of a hot stove. This bread is extensively used in the Scandinavian countries. Black bread is used by the peasantry in many European countries.

Aerated bread is made by forcing carbon dioxide through the dough instead of securing a like result by fermentation with yeast, etc., as in the ordinary method of bread making.

For home bread making, Miss Shepperd in her Hand-Book of Household Science, gives the following directions: "Bread with HomeMade Yeast. One cup of good home-made yeast, one cup of milk and water (one half cup of each) and two level teaspoonfuls of salt. Have the temperature of liquid and flour 75° F. and make into a dough stiff enough to handle without flour, let rise three hours, or until double in size, keeping always at 75° F., and when risen, mold into loaves, let stand one hour and bake." The home-made yeast is made as follows: "Stir one half pint of flour to a smooth batter with one half pint of cold water. Over this pour one quart of boiling water, pouring slowly and stirring rapidly. Place over the fire, and cook four or five minutes. Add two

level tablespoonfuls of sugar and one of salt. When cooled to 75° F., add one ounce of compressed yeast, or one pint of home-made yeast. Keep as nearly 75° F. as possible for 24 hours, stirring down once in four or five hours. Keep in a glass jar in a cool place. The jar must be thoroughly washed and scalded before putting fresh yeast into it."

"Compressed Yeast Bread.-To make bread with compressed yeast, break a one-half ounce cake of compressed yeast into small pieces in a cup, and cover with cold water. Place in a bowl one pint of liquid - one half milk and one half water. Make the temperature of the mixture 75° F. Into this liquid put two level teaspoonfuls of salt, stir in a cup of sifted flour; stir the yeast and water in the cup, and pour into this; put in another cup of flour and beat it well. Continue to stir in flour, keeping sides of bowl clean, and kneading with the spoon until nearly stiff enough. Then bathe the hands, wipe them dry, flour the board, and knead the dough until it ceases to adhere to the hands or board, when no flour is used. Grease the bowl with some nice-flavored fat and treat the top of dough after putting into the bowl in the same way. Cover the bowl with a white cloth and allow the dough to rise. See that the air is not cooler or warmer than 75° F. Let the dough rise three hours, or until it is double its original size, knead well and mold into loaves, put in greased pans, grease over the top, let rise one hour, when it will again double its size if properly manipulated, then bake."

These methods of making bread are particularly adaptable to hard wheat flours. For soft wheat flours, other methods in which more salt is used, a longer time allowed for fermentation, and a stiffer dough is made, will be found to give better results. Because of differences in the composition of the various kinds of flour, no directions can be given which are alike applicable to all. The method of bread making which is suited to one flour does not necessarily give the best results with other flours. In fact,

it is necessary to vary the conditions of preparation according to the kind of flour used. HARRY SNYDER, Chemist, University of Minnesota.

Bread-fruit (Artocarpus incisa), a tree of the natural order Urticaceae, native of the Indian Archipelago and of the southern Pacific Islands. It attains a height of 30 or 40 feet; is often limbless for half its height, bears leathery, glossy dark green, three- to nine-lobed leaves, one to three feet long; has compact, club-shaped, yellow catkins of male flowers, 9 to 15 inches long, and sub-globular heads of female flowers with spongy receptacles; and usually seedless, spheroidal fruits, at first green, later brown, and lastly yellow, six inches or more in diameter, hanging by short thick stalks singly or in clusters of two or three from the smaller branches. The rough rind is irregularly marked in squares and other figures with raised centres. The unripe fruit contains a milky juice, and when in the edible stage it resembles fresh bread, being white and mealy. It is then slightly tart. Later it becomes yellow, juicy, and tastes of decay. In tropical countries where it has been introduced and particularly in its original home, the fruit is highly valued as a nutritious food, being prepared for use in various ways. When baked it resembles plantain rather than wheaten bread, being sweetish, slightly astringent, but otherwise almost tasteless. When fresh fruits cannot be procured, pasty mass, and so used. Another common way it is sometimes slightly fermented, beaten to a of preparing it is to beat it to a paste with cocoaplantains, etc. nut milk and to serve it mixed with bananas, Since the trees produce two or three crops annually, and since the bearing seasons of different varieties overlap more or less, the fruit may be obtained during the greater part of the year. Not alone for the fruit is the tree valuable; in the South Sea Islands its fibrous inferior in softness and whiteness, to that made inner bark is woven into cloth resembling, but from the paper mulberry which is similarly employed in those islands; the gummy exudation from the bark, boiled with cocoanut oil is used for caulking canoes, pails, etc.; the beautiful yellow wood is light and soft, but when exposed to the air becomes dark like mahogany, and is used for canoes, furniture, and the interior work in houses. The tree has been cultivated to a slight extent in southern Florida, but the fruits rarely appear even in the most southern markets of the United States, because they do not bear shipment well, and unless used very soon after being gathered become hard and disagreeable in taste. For an account of the introduction of the bread-fruit tree into the West Indies in the last decade of the 18th century, when such feats were more difficult and less common than zine (pp. 2869-71). A near relative of the a century later, see Curtis, 'Botanical Magabread-fruit tree is the jaca or jack (q.v.).

Bread Making. See BREAD.

Bread-nut (Brosimum alicastrum), a tree of the natural order Urticacea, a native of the West Indies and closely related to the breadfruit. The tree, which is very large, bears shining lance-shaped leaves; globose catkins of male and female flowers on different trees; and yields a gummy, milky juice from its bark. The round. yellow fruits (drupes), which are about three inches in circumference, contain each a single


seed. When roasted or boiled they are used like bread, and, having a flavor which resembles hazel nuts, form a pleasant food. In the United States the tree has not been cultivated.

Bread Riot in New York, The, a riotous demonstration in New York, 13 Feb. 1837. The financial policy of President Jackson had created an era of wild-cat banks, currency inflation, extravagant speculation, and high prices which bore cruelly on the poor, flour being $12 a barrel, partly owing to a short crop the year before, and other prices in proportion. In New York the general distress was intensified by the great fire of 15-16 Dec. 1835, which destroyed nearly 700 business and other buildings, covering some 13 acres in the heart of the city and occasioning a loss of $20,000,000. For some time the Jacksonian press had been denouncing the grain dealers as the cause of the famine prices, mentioning especially Eli Hart, the leading commission merchant, and the houses of Meech and Herrick, although as they were commission dealers their stocks were obviously not private hoards. On 13 Feb. 1837, just before Jackson's term expired, these papers announced a public meeting in City Hall Park at 4 P.M., the call being headed "Bread, Meat, Rent, Fuel! Their prices must come down!" The call was signed by eight men, two of whom

Bread-root (Psoralea esculenta), a leguminous plant with edible, farinaceous tubers. It is the Pomme blanche or Pomme de terre of the French pioneers. It is common on the higher prairies from Texas through Iowa to Wis



Bread-winners, The, a brief novel, appeared anonymously in 1883. The kindly interest shown by Alfred Farnham, a retired army officer, in Maud Matchin, the handsome but vulgar daughter of a master carpenter in a western city, turns her head, and she confesses her love to him, which is not reciprocated. Maud's rejected lover, Sam Sleeny, journeyman in Matchin's employ, is jealous of

Farnham. Dominated by Offitt, a demagogue, he joins a labor organization. Farnham loves Alice Belding, who refuses him, but still returns his love. During a strike Farnham organizes patrolmen. The mob attacks his house, and Sleeny assaults Farnham, but fails to kill him. Offitt, who now pays his addresses to Maud, enters Farnham's home, assaults and robs him, and Alice and Mrs. Belding come and nurse him. Offitt turns suspicion to Sleeny, hastens to Maud, and urges her to fly with him. pecting, she refuses, gets and reveals his secret. Sleeny, who has been arrested, breaks jail, and at Maud's home meets Offitt and kills him.


Sleeny is tried for killing Offitt, and acquitted upon the ground of temporary insanity. The book is a brilliant presentation of the conditions of "labor" at that period. Its authorship was acknowledged in 1902 by John Hay.

Moses Jacques and Alexander Ming, Jr. were well-known and very violent demagogues. Jacques was made chairman, and with Ming, and others, made furious speeches inflaming the passions of the crowd. Some one at length indicated Hart's store, on Washington Street, between Dey and Cortlandt, as a vast hoard of provisions to relieve their distress, and the crowd surged toward it. The police were swept away and beaten, and although two of the three iron doors held, the centre one was battered in, and the crowd began throwing flour barrels and sacks of grain into the street, staving in and tear

ing open such as did not burst by their own fall,
and as one of the papers remarked, "lowering
prices by leaving less on the market." A fresh
onslaught by the police was repelled; and it was
not till well into the evening that a body of mili-erally every half second.

tia dispersed the mob, which by this time had
thrown into the street about 500 barrels of
flour and 1,000 bushels of wheat, the most of
it relieving no one. Herrick's stock was some-
what damaged also, and Meech's store attacked.
The disturbance was attributed to the foreigners,
but although the two ringleaders were foreign,
four of the eight names signed to the call
were American, and the natives certainly looked
on at the mob without trying to assist the offi-


Breadalbane, brĕd-äl'bān, a district in the western part of Perthshire, in the centre of the Grampians, which here cover a large tract of the county in length and breadth. This district is a complete mixture of high and low hills, yielding pasture for large flocks of sheep and shelter for game, with intermediate valleys, some of which are susceptible of cultivation, while others are merely areas of peat and heath. Loch Tay lies in the centre of the district. Kenmore and Killin are the largest villages.

Breadth, a term in art, used to denote means or effects whereby an artist becomes distinguished for largeness and mastery of treatment. Breadth of style in art is shown in work which gives the impression of these qualities, manifested in simplicity, comprehensiveness, and due subordination of detail. In a work of art possessing the true characteristics of breadth, the eye, passing from one feature to another, takes in, as it were, the whole subject and meaning at a single glance.

Break-Circuit Chronometer, the name ap

applied to a box-chronometer to which a device has been attached for breaking an electric circuit at every motion of the escape-wheel, gen

Break'er. See COAL MINING.

Breakespere, brāk'spēr. See ADRIAN IV.

Breaking Bulk, the act of breaking open of a bundle, parcel, etc., and taking the contents, so as to constitute in law a conversion or the like.

Breakwater, an obstruction of any kind raised to oppose the action of the waves, and make safe harbors and roadsteads. The outer

mole of the harbor of Civita Vecchia was built by the Emperor Trajan for this purpose; and the piers of ancient Piræus and of Rhodes are of the same class of structures. Herod, it is stated by Josephus, in order to form a port between Dora and Joppa, ordered mighty stones to be cast into the sea in 20 fathoms water, to prepare a foundation; the greater number of them 50 feet in length, 9 feet deep, and 10 feet wide, and some were even larger than these. In the use of such immense blocks of stone, the true principles of constructing a permanent barrier to the waves, appear to have been better understood than they were 17 centuries afterward. Breakwaters are generally solid and made of stone, but there are also floating breakwaters which serve the same purpose. These

are built of strong open woodwork, divided into several sections, and secured by chains attached to fixed bodies. The breakers pass between the beams of such a structure as if through a sieve, and in the passage nearly all their force is destroyed. It is estimated that a breakwater of this description will last for 25 years. Stone breakwaters are usually constructed by sinking loads of unwrought stone along the line where they are to be laid, and allowing them to find their angle of repose under the action of the waves. When the mass rises to the surface, or near it, it is surmounted with a pile of masonry, sloped outward in such a manner as will best enable it to resist the action of the waves, or it is covered, as at Plymouth, England, with large blocks of stone, which do not rise high above the surface of the water. Sometimes the breakwater has to be constructed of solid masonry from its foundation. The breakwater at Dover, England, is built in this way, there being no stone in the neighborhood to form a base of the kind described. The most gigantic breakwater ever constructed is that which was erected by French engineers to protect the harbor of Cherbourg. The history of the building of this

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base, and 339 feet at the top, the angle of the slope being 60°. This was strengthened by an interior concentric cone, 5 feet 10 inches within the outer one. The frame of each was made of 80 large upright timbers 24 feet long and I foot square. On these were erected 80 more of 14 feet in length, making, for the 2 exterior and 2 interior portions, 320 of these uprights. The machine was then planked, hooped, and firmly bolted together. The first cone was built and floated at Havre, then taken to pieces, transported to Cherbourg, and floated off and sunk on 6 June 1784; and the second on 7 July following, in the presence of 10,000 spectators; but before the cavity of this one could be filled with stones, its upper part was demolished in a storm of five days' continuance in August, and the stones it contained were spread over the bottom, interfering with the placing of the next cone. The original plan was to set 90 of these cones, of 150 feet diameter at base, 60 at top, and 65 feet high, in succession, and fill them with loose stones or masonry, and the spaces between them with a network of iron chains, to break the force of the waves. Several modifications of the plan were attempted, the net


breakwater affords an amusing and instructive example of the folly of ignoring experience and the laws of nature. When Louis XVI. appointed commissioners to report upon the best locality for establishing, opposite the English coast, a port and naval arsenal, they recommended the construction of a dike over two miles in length, in water 70 feet deep, in front of the harbor of Cherbourg, by sinking a vast number of ships filled with masonry as a basis, and covering these with heavy stones to within 18 feet of the surface. And when at last four of the ablest naval officers and engineers of France were appointed to execute the work, which was regarded as one of the most stupendous operations, certainly the greatest piece of hydraulic architecture ever undertaken by man, the plan they adopted was one which proved impracticable after having been prosecuted from the year 1784 to 1789, at enormous expense. This plan was the construction of huge truncated cones of timber, which, of the reduced size at which they were actually built, measured 36 feet in height, with a circumference of 472 feet at the

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result, after years of labor and an expense of upward of $6,000,000, being a number of isolated mounds of stone, extending in a crescent for about 23 miles. In 1830 the work was again taken up, and completed in its present form about 1856. For a full account of this stupendous work, consult Cresy's Encyclopædia of Civil Engineering.'

There are many important breakwaters in the United States, and each decade finds an increasing number of them as the demands of trade, and the liberality of the government demands and permits their construction. The latest of these (1903) is the great breakwater at Buffalo, N. Y., built to form a harbor for the immense lake traffic centring at that city. This structure forms the most important section of a long line of breakwaters that extend for 41⁄2 miles along the water-front. At the time that the present work was undertaken there existed the north breakwater, which is built of concrete and extends for 2,200 feet, with a light at its southerly end. Opposite this light and to the westward of it is the northerly end of what is

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