Science in the Kitchen Part 3

_Stewing_ is the prolonged cooking of food in a small quant.i.ty of liquid, the temperature of which is just below the boiling point.

Stewing should not be confounded with simmering, which is slow, steady boiling. The proper temperature for stewing is most easily secured by the use of the double boiler. The water in the outer vessel boils, while that in the inner vessel does not, being kept a little below the temperature of the water from which its heat is obtained, by the constant evaporation at a temperature a little below the boiling point.

_Frying_, which is the cooking of food in hot fat, is a method not to be recommended--Unlike all the other food elements, fat is rendered less digestible by cooking. Doubtless it is for this reason that nature has provided those foods which require the most prolonged cooking to fit them for use with only a small proportion of fat, and it would seem to indicate that any food to be subjected to a high degree of heat should not be mixed and compounded largely of fats. The ordinary way of frying, which the French call _sauteing_, is by the use of only a little fat in a shallow pan, into which the food is put and cooked first on one side and then the other. Scarcely anything could be more unwholesome than food prepared in this manner. A morsel of food encrusted with fat remains undigested in the stomach because fat is not acted upon by the gastric juice, and its combination with the other food elements of which the morsel is composed interferes with their digestion also. If such foods are habitually used, digestion soon becomes slow and the gastric juice so deficient in quant.i.ty that fermentation and putrefactive changes are occasioned, resulting in serious disturbance of health. In the process of frying, the action of the heat partially decomposes the fat; in consequence, various poisonous substances are formed, highly detrimental to the digestion of the partaker of the food.

ADDING FOODS TO BOILING LIQUIDS.--Much of the soddenness of improperly cooked foods might be avoided, if the following facts were kept in mind:--

When vegetables, or other foods of ordinary temperature, are put into boiling water, the temperature of the water is lowered in proportion to the quant.i.ty and the temperature of the food thus introduced, and will not again boil until the ma.s.s of food shall have absorbed more heat from the fire. The result of this is that the food is apt to become more or less water-soaked before the process of cooking begins. This difficulty may be avoided by introducing but small quant.i.ties of the food at one time, so as not to greatly lower the temperature of the liquid, and then allowing the latter to boil between the introduction of each fresh supply, or by heating the food before adding it to the liquid.

EVAPORATION is another principle often overlooked in the cooking of food, and many a sauce or gravy is spoiled because the liquid, heated in a shallow pan, from which evaporation is rapid, loses so much in bulk that the amount of thickening requisite for the given quant.i.ty of fluid, and which, had less evaporation occurred, would have made it of the proper consistency, makes the sauce thick and unpalatable. Evaporation is much less, in slow boiling, than in more rapid cooking.

MEASURING.--One of the most important principles to be observed in the preparation of food for cooking, is accuracy in measuring. Many an excellent recipe proves a failure simply from lack of care in this respect. Measures are generally more convenient than weights, and are more commonly used. The common kitchen cup, which holds a half pint, is the one usually taken as the standard; if any other size is used, the ingredients for the entire recipe should be measured by the same. The following points should be observed in measuring:--

1. The teaspoons and tablespoons to be used in measuring, are the silver spoons in general use.

2. Any material like flour, sugar, salt, that has been packed, should either be sifted or stirred up lightly before measuring.

3. A cupful of dry material is measured level with the top of the cup, without being packed down.

4. A cupful of liquid is all the cup will contain without running over.

Hold the cup in a saucer while measuring, to prevent spilling the liquid upon the floor or table.

COMPARATIVE TABLE OF WEIGHTS AND MEASURES.--The following comparative table of weights and measurements will aid in estimating different materials:--

One heaping tablespoonful of sugar weighs one ounce.

Two round tablespoonfuls of flour weigh one ounce.

Two cupfuls of granulated sugar weigh one pound.

Two cupfuls of meal weigh one pound.

Four cupfuls of sifted flour weigh one pound.

One pint of oatmeal, cracked wheat, or other coa.r.s.e grains, weighs about one pound.

One pint of liquid weighs one pound.

One pint of meat chopped and packed solid weighs one pound.

Seven heaping tablespoonfuls of sugar = one cupful.

Five heaping tablespoonfuls of flour = one cupful.

Two cupfuls of liquid or dry material = one pint

Four cupfuls of liquid or dry material = one quart.

MIXING MATERIALS.--In the compounding of recipes, various modes are employed for mingling together the different ingredients, chief of which are _stirring_, _beating_, and _kneading_.

By _stirring_ is meant a continuous motion round and round with a spoon, without lifting it from the mixture, except to sc.r.a.pe occasionally from the sides of the dish any portion of the material that may cling to it.

It is not necessary that the stirring should be all in one direction, as many cooks suppose. The object of the stirring is to thoroughly blend the ingredients, and this may be accomplished as well by stirring--in one direction as in another.

_Beating_ is for the purpose of incorporating as much air in the mixture as possible. It should be done by dipping the spoon in and out, cutting clear through and lifting from the bottom with each stroke. The process must be continuous, and must never be interspersed with any stirring if it is desired to retain the air within the mixture.

_Kneading_ is the mode by which materials already in the form of dough are more thoroughly blended together; it also serves to incorporate air.

The process is more fully described in the chapter on "Bread,"

TEMPERATURE.--Many a cook fails and knows not why, because she does not understand the influence of temperature upon materials and food.

Flour and liquids for unfermented breads cannot be too cold, while for bread prepared with yeast, success is largely dependent upon a warm and equable temperature throughout the entire process.

COOKING UTENSILS.--The earliest cookery was probably accomplished without the aid of any utensils, the food being roasted by burying it in hot ashes or cooked by the aid of heated stones; but modern cookery necessitates the use of a greater or less variety of cooking utensils to facilitate the preparation of food, most of which are so familiar to the reader as to need no description. (A list of those needed for use will be found on page 66.) Most of these utensils are manufactured from some kind of metal, as iron, tin, copper, bra.s.s, etc. All metals are dissolvable in certain substances, and some of those employed for making household utensils are capable of forming most poisonous compounds when used for cooking certain foods. This fact should lead to great care on the part of the housewife, both in purchasing and in using utensils for cooking purposes.

Iron utensils, although they are, when new, apt to discolor and impart a disagreeable flavor to food cooked in them, are not objectionable from a health standpoint, if kept clean and free from rust. Iron rust is the result of the combination of the iron with oxygen, for which it has so great an affinity that it will decompose water to get oxygen to unite with; hence it is that iron utensils rust so quickly when not carefully dried after using, or if left where they can collect moisture. This is the reason why a coating of tallow, which serves to exclude the air and moisture, will preserve ironware not in daily use from rusting.

"Porcelain ware" is iron lined with a hard, smooth enamel, and makes safe and very desirable cooking utensils. German porcelain ware is unexcelled for culinary purposes.

"Granite ware" is a material quite recently come into use, the composition of which is a secret, although p.r.o.nounced by eminent chemists to be free from all injurious qualities. Utensils made from it are light in weight, easily kept clean, and for most cooking purposes, are far superior to those made from any other material.

What is termed "galvanized iron" is unsuitable for cooking utensils, it being simply sheet iron coated with zinc, an exceedingly unsafe metal to be used for cooking purposes.

Tin, which is simply thin sheet iron coated with tin by dipping several times into vats of the melted metal, is largely employed in the manufacture of cooking utensils. Tinware is acted upon by acids, and when used for holding or cooking any acid foods, like sour milk, sour fruits, tomatoes, etc., harmful substances are liable to be formed, varying in quant.i.ty and harmfulness with the nature of the acid contained in the food.

In these days of fraud and adulteration, nearly all the cheaper grades of tinware contain a greater or less amount of lead in their composition, which owing to its greater abundance and less price, is used as an adulterant of tin. Lead is also used in the solder with which the parts of tinware are united. The action of acids upon lead form very poisonous compounds, and all lead-adulterated utensils should be wholly discarded for cooking purposes.

_Test for Lead-Adulterated Tin._--Place upon the metal a small drop of nitric acid, spreading it to the size of a dime, dry with gentle heat, apply a drop of water, then add a small crystal of iodide of potash. If lead is present, a yellowish color will be seen very soon after the addition of the iodide. Lead glazing, which is frequently employed on crockery and ironware in the manufacture of cooking utensils, may also be detected in the same manner.

Cooking utensils made of copper are not to be recommended from the point of healthfulness, although many cooks esteem them because copper is a better conductor of heat than iron or tin. The acids of many fruits combine with copper to form extremely poisonous substances. Fatty substances, as well as salt and sugar, act upon copper to a greater or less degree, also vegetables containing sulfur in their composition and produce harmful compounds.

Utensils made of bra.s.s, which is a compound of copper and zinc, are not safe to use for cooking purposes.

TABLE TOPICS.

Bad cooking diminishes happiness and shortens life.--_Wisdom of Ages._

Says Mrs. Partington: "Many a fair home has been desiccated by poor cooking, and a man's table has been the rock on which his happiness has split."

SIGNIFICANT FACT.--_Lady_--"Have you had much experience as a cook?"

_Applicant_--"Oh, indeed I have. I was the cook of Mr. and Mrs.

Peterby for three years."

_L._--"Why did you leave them?"

_A._--"I didn't leave them. They left me. They both died."

_L._--"What of?"