moth are likely to be serious pests, windows should be covered with screens, doors made tight, and every precaution taken to keep them from gaining entrance to the granary.

Aside from the losses occasioned by insects and vermin, the loss of weight through storage is a negligible quantity.

A country elevator.

tor is an American institution which has immensely facilitated the handling of wheat and other grains, due to the fact that "threshed grain can, in large measure, be handled like water." Wheat may be run directly from the threshing machine into tight wagon boxes holding fifty to 100 bushels and hauled directly to the elevator, where it is automatically dumped and elevated by power machinery, so that a pound of grain need not be lifted by hand after it starts into the threshing machine. Or it may be temporarily stored in two-bushel bags and subsequently drawn to the elevator.

The elevator company will receive, insure and store wheat for fifteen days at a fixed charge, and store indefinitely thereafter for a fixed charge, depending upon the length of storage. It will also clean the wheat if desired. The owner receives a certificate of the amount of wheat stored, which he can sell whenever he desires to do so.

Terminal elevator.

Country elevators are usually built of wood and have a capacity of 20,000 to 40,000 bushels; while elevators at terminal points have been built which hold 3,000,000 bushels and are now being made of steel, concrete, or tile, thus saving largely in insurance. On the Pacific Coast, the wheat is still handled in sacks as in other countries.

VII.

WHEAT.

I. USES AND PREPARATION FOR USE.

170. Uses. The use of wheat as a human food is pre historic, but by no means universal, although much more so than formerly. It is only since the application of machinery to wheat harvesting and the simultaneous development of new wheat areas, that the coarser grains have come to take a more secondary place in our dietary. The ancient Egyptians lived upon barley, sorghum seed, lupines and horse beans. Esau's mess of pottage was hulled lupines. Our New England forefathers ate "rye and Indian" (a mixture of rye and maize meal) and buckwheat principally. Wheat is almost exclusively used for the production of flour from which various forms of food are made, while its by-products serve as food for domestic animals. The value of wheat as human food does not lie so much in its superiority in sustaining life as it does in its greater palatability and the attractiveness and great variety of forms which can be made therefrom.

171. Food for Domestic Animals. All classes of domestic animals are fond of wheat, whether fed whole or ground, wet or dry. Feeding experiments clearly indicate that the food value of wheat is slightly, if any, greater than maize, pound for pound, when fed to domestic animals. When the price permits its use under these conditions, it is a healthful and desirable food, but the best results are obtained when it does not form more than half the grain ration. When fed whole, large quantities of the grains escape mastication, but grinding has been found to increase slightly its food value. The Minnesota Station found

that when fed to pigs, ground wheat was about ten per cent more digestible than whole wheat.1 The Ohio State University reports one experiment in which 399 pounds of both ground and moistened wheat produced 100 pounds of increase in pork as compared with 453 pounds of whole dry wheat. The South Dakota Station found 491 pounds of whole dry wheat and 481 pounds of ground dry wheat produced 100 pounds of increase.

172. Source, Amount and Quality of Flour.-In the process of milling the aim is to reduce the endosperm to a very fine powder with as little admixture of other portions of the grain as possible. The following table gives the analysis of cleaned wheat and of three grades of flour produced therefrom by the roller process of milling."

2

(2) Bakers' flour: Slightly yellow in color. The grain lacks distinctness, making the flour lumpy.

(3) Low grade flour: The grain is soft and the flour dark and lumpy. Particles of embryo and bran are prominent.

The low grade flour was somewhat higher in protein, considerably higher in crude fiber and much higher in phosphoric acid than the patent flour. The patent flour, which presumably formed the bulk of the product, was lower in protein and phosphoric acid than the grain. All grades of flour were lower in

1 Minn. Bul. 36, p. 147.

? U.S. Dept. of Agr., Div. of Chem. Bul. 4 (1884), pp. 38-39.

crude fiber than the grain. The highest grades consist of approximately pure endosperm, but since in producing these highest grades it is necessary to reject practically all of those portions of the endosperm that remain attached to the embryo and to the aleurone layer, it is customary in the roller process of milling to make several grades of flour with varying admixtures of portions foreign to the endosperm, in order to increase the total percentage of the flour. The superiority of the modern methods of milling lies largely in the exactness with which the various products of the wheat grain can be sorted. The almost complete elimination of crude fiber in the patent flour is probably one of the most important factors in affecting its commercial and breadmaking value. Another rather important factor is the fineness of the particles of flour. While flour seems like an impal

pable powder, there is in reality considerable variation in the size of the particles, as may be readily determined by passing flour through sieves of proper dimensions. Microscopic examination will show that some particles are spherical, while others are angular. Flour from hard wheat is generally larger and more angular than that from soft wheat. The character of the milling has, of course, the greatest effect upon the granulation of the flour. The most desirable condition for breadmaking probably exists when the flour is of medium granulation, with a mixture of medium and smaller sized particles, as the capacity of the flour to absorb water is thus increased.1

The quantity and quality of the flour therefore depend upon the character of the wheat grain both physically and chemically, upon its condition at the time of milling, upon the mill and upon the skill of the miller. Usually seventy to seventy-two per cent of the grain is made into flour, although variations ranging from sixty-five to eighty per cent have been reported for different varieties of wheat milled by the roller process. Where

1 The Northwestern Miller, Christmas, 1900, p. 20.

U. S Dept. of Agr., Div. of Chem. Bul. 4 (1884), p. 60.

millers do custom milling for an eighth toll, it is customary to give thirty-six to thirty-seven pounds of flour and twelve to fourteen pounds of mill feed for each bushel. While wide variations may occur on account of differences in the process of milling and mixing, ordinarily about one-half the by-product is bran, and the other half shorts and middlings.

The larger the endosperm and the smaller the embryo and aleurone layer, the larger the percentage of flour obtained. The evidence seems conclusive that the embryo and aleurone layer are considerably higher in ash, and especially in phosphoric acid, nitrogenous compounds and fat, than the endosperm, and that the composition of wheat may vary on account of the proportion of these to endosperm without any variation in the composition of the endosperm. There is, therefore, no necessary relation between the composition of the wheat grain and the composition of the flour therefrom. In general, however, grains with high percentage of nitrogenous compounds produce flour with high percentage of these compounds and with high gluten content. (69)

173. Grades of Flour.-The expert miller determines the quality of the flour largely by feel and color. Great expertness is acquired in judging of the granulations by the feel, which depends both on the size of the flour particles and their form. The quality of the flour also depends upon the per cent and quality of the gluten. (70) The quality of the gluten may be determined by the "baker's sponge test" by which the volume of dough per unit of gluten as well as the time required to obtain the maximum rise is determined. (204)

Many trade names are given to different grades of flour by manufacturers. Dealers have sought to obtain uniformity of grading by a system of inspection similar to that employed for whole wheat and other grains. As a guide for the inspector, a series of standards is prepared and renewed from time to time as required. The classification differs in different cities.

Ir