21. PURPOSE OF COOKING.--As the so-called ready-to-eat cereals require practically no further preparation, attention is here given to only those cereals which need additional treatment to prepare them properly for the table. Raw grains cannot be taken into the body, for they are neither appetizing nor digestible. The treatment to which they must be subjected is cooking, for the structure of grains is such that cooking is the only means by which the coverings of the starch granules can be softened and broken to make them digestible. But this is not the only effect produced by cooking; besides making raw cereals digestible, cooking renders them palatable, destroys any bacteria or parasites that might be present, and, by means of its various methods, provides a variety of dishes that would otherwise be very much limited.
22. CHANGES THAT CEREALS UNDERGO IN COOKING.--In the process of cooking, cereals undergo a marked change, which can readily be determined by performing a simple experiment. Place an equal amount of flour or corn starch--both cereal products--in two different glasses; mix that in one glass with cold water and that in the other with boiling water. The mixture in which cold water is used will settle in a short time, but if the substance that goes to the bottom is collected and dried it will be found to be exactly the same as it was originally. The mixture in which boiling water is used, however, will not only become a sticky mass, but will remain such; that is, it will never again resume its original form. This experiment proves, then, that grains that come in contact with water at a high temperature, as in cooking, absorb the water and burst their cellulose covering. This bursting frees the granulose, or the contents of the tiny granules, which are deposited in a network of cellulose, and as soon as this occurs it mixes with water and forms what is called soluble starch. Starch in this state is ready for digestion, but in the original, uncooked state only a very small part of it, if any, is digestible.
23. PREPARATION FOR COOKING CEREALS.--Before the cooking of cereals is attempted, it is advisable for the sake of convenience to get out all utensils as well as all ingredients that are to be used and arrange them so that they will be within easy reach. The way in which this should be done is illustrated in Fig. 1. The utensils and ingredients shown, which are suitable for most methods of cooking cereals and particularly for cooking them by the steaming process, consist of a double boiler a; a measuring cup b, a knife c, and spoons d and e, for measuring; a large spoon f, for stirring; a salt container; and a package of cereal. The housewife will be able to tell quickly from a recipe just what ingredients and utensils she will need, and by following the plan here suggested and illustrated she will find that her work can be done systematically and with the least expenditure of time.
24. FIRST STEPS IN THE PROCESS OF COOKING.--While cereals may be cooked in a variety of ways, the first steps in all the processes are practically the same. In the first place, the required amount of water should be brought to the boiling point, for if the water is boiling the cereal will thicken more rapidly and there will be less danger of lumps forming. Then salt should be added to the water in the proportion of 1 teaspoonful to each cupful of cereal. Next, the cereal should be stirred into the boiling salted water slowly enough to prevent it from forming lumps, and then, being constantly stirred, it should be allowed to cook until it thickens. The process up to this point is called setting a cereal, or grain. After the cereal is set, it may be boiled, steamed, or cooked in the fireless cooker, but the method of cookery selected should be chosen with a view to economy, convenience, and thoroughness. The terms setting and set should be thoroughly fixed in the mind, so that directions and recipes in which they are used will be readily understood.
25. COOKING CEREALS BY BOILING.--Very often the cereal, after it is set, is allowed to cook slowly until it is ready to serve; that is, the method of boiling is practiced. This method, however, is not to be recommended, because it is not economical. Cereals cooked in this way require constant watching and stirring, and even then it is difficult to keep them from sticking to the cooking utensil and scorching or becoming pasty on account of the constant motion. Sometimes, to overcome this condition, a large quantity of water is added, as in the boiling of rice; still, as some of this water must be poured off after the cooking is completed, a certain amount of starch and soluble material is lost.
26. COOKING CEREALS IN THE DOUBLE BOILER.--Probably the most satisfactory way in which to cook cereals, so far as thoroughness is concerned, is in a double boiler, one style of which is shown at a, Fig. 1. This method of cookery is known as steaming, or dry steaming, and by it the food itself, after it is set, never comes within 6 or 8 degrees of the boiling point. In this method, the cereal is first set in the small, or upper, pan of the double boiler. This pan, which is covered, is placed into the large, or lower, pan, which should contain boiling water, and the cereal is allowed to cook until it is ready to serve. The water in the large pan should be replenished from time to time, for if it is completely evaporated by boiling, the pan will be spoiled and the cereal in the upper pan will burn.
This method of cooking has several advantages that should not be disregarded. Cereals to which it is applied may be partly cooked on one day and the cooking completed the next morning before breakfast, or they may be completely cooked on one day and merely heated before they are served. Then, when cooked at a temperature slightly below the boiling point, the grains remain whole, but become thoroughly softened, because they gradually absorb the water that surrounds them. In addition, the long cooking that is necessary to prepare them at a low temperature develops a delicious flavor, which cannot be obtained by rapid cooking at the boiling point.
27. COOKING CEREALS IN THE FIRELESS COOKER.--In a kitchen that is equipped with a fireless cooker, it is advisable to use this utensil for cereals, for cooking them by this method secures the greatest economy of fuel and effort. As in the preceding methods, the cereal is first set in the pan that fits into the cooker compartment. While the cereal is at the boiling point, this pan is covered tightly and placed in the fireless cooker, where it is allowed to remain until the cereal is ready to be served. The heat that the cereal holds when it is placed in the cooker is retained, and this is what cooks it. Therefore, while this method of cooking requires considerable time, it needs neither additional heat nor labor after the cereal is placed in the cooker. In reality, it is an advantageous way in which to cook cereals, since, if they can be set and placed in the cooker in the evening, they will be ready to serve at breakfast time on the following day.
28. COOKING CEREALS BY DRY HEAT.--An old method of cooking cereals or starchy foods is called browning, or toasting, and it involves cooking them by dry heat. A thin layer of grain is spread in a shallow pan and this is placed in a slow oven. After the grains have browned slightly, they are stirred, and then they are permitted to brown until an even color is obtained. By this method the flavor of the cereals is developed and their digestibility increased. Since grains keep much better after they have been subjected to the process of toasting, this means is used extensively for preserving grains and cereal foods.
29. POINTS TO OBSERVE IN COOKING CEREALS.--In cooking cereals by any method, except browning, or toasting, it is always necessary to use liquid of some kind. The quantity to use, however, varies with the kind of cereal that is to be cooked, whole cereals and those coarsely ground requiring more liquid than those which are crushed or finely ground. If the liquid is to be absorbed completely when the grain is cooked, it should be in the correct proportion to the grain. To be right, cooked cereals should be of the consistency of mush, but not thin enough to pour. Much attention should be given to this matter, for mistakes are difficult to remedy. Cereals that are too thick after they are cooked cannot be readily thinned without becoming lumpy, and those which are too thin cannot be brought to the proper consistency unless the excess of liquid is evaporated by boiling.
Gruels are, of course, much thinner than the usual form of cereal. They are made by cooking cereals rapidly in a large quantity of water, and this causes the starch grains to disintegrate, or break into pieces, and mix with the water. The whole mixture is then poured through a sieve, which removes the coarse particles and produces a smooth mass that is thin enough to pour.
The length of time to cook cereals also varies with their kind and form, the coarse ones requiring more time than the fine ones. Because of this fact, it is difficult to say just how much time is required to cook the numerous varieties thoroughly. However, little difficulty will be experienced if it is remembered that cereals should always be allowed to cook until they can be readily crushed between the fingers, but not until they are mushy in consistency.