A modern flour-mill is a very complicated institution and cannot be gone into in detail here. The grinding surfaces are steam rollers arranged in series through which the grain is passed and many products are obtained. Sometimes as many as fifty are turned out from a single mill. Since these rollers are slightly heated, the effect is very different from that obtained by the old-fashioned stones. The endosperm or starchy part of the kernel is made brittle and can easily be pulverized, whereas the germ, which contains the fat, is flattened out when passed through the rollers and is separated from the meal at the first sifting. This gives a meal which is almost entirely lacking in fat, while the caked germ is used for the oil which can be extracted from it, then is finally made into fodder for cattle. With wheat this process is carried to its greatest extent until we have a large variety of flours in use on the market. We will discuss these more fully in the next chapter.

Milling

With the shortage of wheat due to war conditions we have learned to use and to appreciate more of the cereal products than we have known before. Flour has been made from barley, corn, oats, and rice as well as from the more familiar rye and wheat, and all of these can be used to take the place of some of the wheat in bread-making. Because of their lack of gluten, to make a successful loaf of bread they cannot be used in a greater proportion than a third of the substitute to two thirds of wheat. As a usual thing wheat, rye, and corn are the three grains that are used for breads; the others are used whole or ground as meal for other purposes. The use of barley, rye, and wheat for bread is thought to mark the stages in the growth of the wealth of a nation. As people become more prosperous they discard barley bread for rye, while wheat bread has always been the sign of luxury.

There is no real reason for this difference in use except for the flavor, as barley contains just as much nourishment as wheat. It contains less fat than corn or oats, and slightly more starch than oats or wheat. It is of very ancient origin, growing in a wider range of climate than any other cereal and was the chief bread plant of the ancients and of Europe down to the sixteenth century. Because of its great enzymic power it is used for malting and makes a basis for all beers and ales. When the hull is removed it is sold as pearl barley. Its importance as a national resource is shown by the extent of its production in the United States. As a crop, it ranks fourth, corn, wheat, and oats being its superiors. It is used to make gruel for infants and invalids.

Grains used for bread-making

Barley

Corn, rightly known as maize, is native to America, though its cultivation has spread rapidly to Europe, northern Africa, and Asia. It is grown to so great an extent in this country that the supply that is turned into cornmeal could be increased tenfold without changing the amount of land now devoted to corn-raising. An increase in the demand for cornmeal would make it more profitable for the farmer to sell his corn to the miller than to use it for feed. Many commercial products are made from corn, among which are corn syrups and commercial glucose. It is not surely known that oats were cultivated by the Egyptians or Hebrews, Greeks, or Romans. They are thought to have been used first by the peoples of eastern Europe or Tartary. They were cultivated by prehistoric western Europe, but not until after wheat and barley were in use. The production of oats increased rapidly, until in Scotland to-day it occupies one third of the land cultivated in crops and in Ireland one half of all grain and green crops. This grain contains a larger percentage of crude fiber than maize at the expense of starch, while the kernel is richer in protein and fat than any other of our cereals. It is used chiefly in the form of oatmeal.

Corn

Oats

Rice is known to have been cultivated in China before 2800 B.C. It was introduced into Europe by the Saracens, and was brought to the United States in 1694 as a present to the Governor of South Carolina. It has been grown in this country since that time. There has been much talk of late of the harm caused by the use of "polished" rice. The reason for this is that in order to have a pure white rice, the kernels are subjected to a process by which all of the bran is very carefully removed. This takes away from the rice a large proportion of its mineral matter and its vitamines. This loss is an important one where rice is practically the sole article of diet, as is the case among the very poor of China and the Philippines, and is no doubt the cause of such diseases as beriberi. Where rice is used, however, two or three times a week and is only one article of a very mixed diet, the loss is too small to be considered. Cured or brown rice, however, is to be had on the market for those who want it, but requires longer cooking than the "polished" rice.

The cultivation of rye is not so ancient as the cultivation of wheat or barley. It contains less protein and fat than wheat, but it does contain gluten which makes it possible to make a porous bread from it. It is found in the market both as fine and coarse flour. Like barley it is used for the manufacture of alcohol and alcoholic beverages and as a feed for cattle.

All of these, together with wheat, are used in one form or another for breakfast cereals. When used whole, the husks only are removed and the grains require a very long, slow cooking. In this form they are served as porridge. Oats are the most common, though corn in the form of hominy has long been in use. These have been considerably replaced by prepared cereals known as "rolled oats" and wheat. The kernel is partly cooked by steam at the factory and pressed while wet between rollers. It is to be noted that this type of cereal has not been thoroughly cooked, and is much better if given a longer cooking than is specified on the box.

Rice

Rye

Breakfast cereals

There are many other specially prepared cereals on the market. These are usually sold in packages with trade names. The processes of their manufacture are secret; but in a general way the grains are cleaned, the husks removed, and the grains cooked or dried and crushed. Some have salt, molasses, or sugar added, while some are colored with caramel. Some are rolled very thin. Those that are like dried crumbs have probably been made into dough, baked, crushed, and then browned. Some are shredded and many are parched or toasted. Malted breakfast foods are treated by malt in the process of manufacture. Malt is barley which has been allowed to germinate and then kiln-dried. Those cereals which are called "puffed" have been heated under pressure at a high temperature and the pressure suddenly diminished. The general composition of all these is very much the same with a fairly high protein content, from 9 to 15 per cent, and carbohydrates 65 to 75 per cent. The fat is the most variable constituent, being greatest in these foods from corn and oats and lowest in rice, varying from 5 to 0.2 per cent. The ash proportion is small, from 0.5 to 2 per cent.

Uncooked cereals should all be given a long, slow cooking to break up the starch granules. They are best stirred into rapidly boiling salted water and allowed to cook directly over the fire from five to ten minutes. They can then be placed in the top of a double boiler on the back of the stove, or, better still, in the tireless cooker for overnight. It is to be remembered that no cereal can be overcooked, even though it is partly cooked to begin with. The longer it is cooked the more digestible it is. The general proportion for the amount of water to be used with cereals is one part of cereal to four parts of water for the granular varieties and one part of cereal to two parts of water for the flaked. These proportions, however, do not hold true where the cereal is allowed to boil vigorously for some time, as the water boils away rapidly.

Although cereals purchased in packages are apt to be cleaner and are more easily handled in the home, it is to be noted that they cost more than those bought in bulk. The ready-to-eat kind are higher in price than the partially cooked, though their nutrient value is practically the same, pound for pound. Many are so light, however, that the value received for the money paid is very low. The cost of malted cereals is more to the producer; hence a higher price to the purchaser.

It is perfectly possible to use cereal breakfast food in other ways than for breakfast dishes. Rice, hominy, and fried cornmeal mush are already in constant use to supply the starch at lunch or dinner. Others can be used for spiced steam pudding, small cakes, and other desserts. When cooked with dates or figs they can be molded and served cold with cream. In the form of mushes, gruels, and cereal jellies they have a valuable place in the diet of children, old people, and invalids.