This section is from the book "Elements Of The Theory And Practice Of Cookery", by Mary E. Williams. Also available from Amazon: Elements Of The Theory And Practice Of Cookery; A Textbook Of Domestic Science For Use In Schools.
The difficulty of cooking food in fat without having it greasy makes this the least desirable method of cooking. Nevertheless, certain kinds of food are good fried, and, if properly fried, need not be unwholesome.
A. Take the temperature of butter or drippings while it is foaming and bubbling over the fire. Heat it until it no longer bubbles, and take its temperature again. Is it hotter or cooler than before? Does water stop boiling unless it is allowed to cool? Does it grow hotter after it reaches the boiling-point? Do you think the fat was boiling when it bubbled?
Why we should not speak of "boiling" fat. - Fats, generally speaking, burn before they boil. It is water contained in the fat that makes it bubble when heated. Until this water has boiled away, the fat cannot be raised to a temperature much above 212°, but after it has all passed off, as is shown by the fat becoming still, the latter grows rapidly hotter, rising to 300° or 400°, some kinds of fat even higher.
B. Drop a bit of bread into bubbling-hot lard; after a minute take it out. Continue to heat the lard until it smokes and is perfectly still. Drop in another bit of bread, let it stay a minute, then take it out. Break open both pieces. Which piece has soaked up the most grease? Which has browned? How does a coating of grease affect the digestion of food? How does browning (carameliza-tion) affect the digestion of starch? Should food be fried in bubbling or in still fat? What makes the fat bubble when the bread is dropped into it? How does moisture affect the temperature of hot fat?
C. Heat butter, lard drippings, and olive or cottonseed oil in separate sauce-pans. Which burns first? Which can be made hottest without burning? Which is best for frying? Which is least desirable?
These experiments show (1) that unless fat used for frying is hot enough to form a crust on the food cooked in it, it will soak into the food; (2) that so long as it bubbles it is not hot enough to form a crust; (3) that anything that cools the fat tends to make the food greasy; (4) that the best fat to fry in is the one that can be made hottest without burning.
Therefore, do not use fat that burns easily; have the fat deep enough to cover the food, so that it may be crusted over at once; see that it is smoking hot and still before putting the food in; reheat the fat after each frying.
Olive oil, which may be heated to above 600°, is the best fat for frying. Southern Europeans use it commonly. In this country the cheaper cottonseed oil, alone or combined with other fats, is much used. Of the animal fats, a mixture of one-third beef suet and two-thirds lard is the best for frying. Lard alone, being soft, is too easily absorbed by the food.
Fats are "tried out," or rendered, to free them from connective tissue, then clarified to remove water and impurities. Fat for frying is now commonly bought ready for use, but if desired, suet may be bought for this purpose; all scraps of fat, cooked or uncooked, and drippings from beef, veal, fresh pork, and chicken1 may be saved and used also. Soup fat and drippings need only to be clarified; suet and scraps must first be tried out.
Cut the fat into bits, put it into a frying-pan, or better, a double boiler, and let it cook slowly for several hours. When the fat is melted, and nearly free from water, strain it, pressing to obtain all the fat.
Melt drippings or tried-out fat, add to it a few slices of raw potato, and heat slowly in the oven until it ceases to bubble. The potato absorbs some of the impurities; most of the rest settle to the bottom. Strain the fat through cheese-cloth, and let it stand undisturbed till solid. If stirred, it absorbs moisture from the air. Since it keeps longer if left unbroken, it is well to strain it into cups or marmalade jars, so that a portion may be used without disturbing the rest.
1 The flavor of fat from mutton, lamb, duck, goose, and turkey prevents their being used in cooking. They may be saved for soap-grease. The fat from smoked meats may be used for frying, if you do not object to its taste.
Foods suitable for frying are those made of cooked material or those that require little cooking; for example, croquettes and oysters. Most raw food, in order that the outside may not become too brown before the inside is cooked, must be put into fat not quite so hot as it should be to prevent absorption of grease. Exceptions. - Fish and oysters, being very watery, cool the fat rapidly; make it therefore as hot for these as for cooked articles.
When the fat begins to smoke, drop into it an inch cube from the crumb of white bread. If this becomes golden brown in forty seconds, the fat is right for croquettes and other articles made of cooked material, and for fish and oysters. If it takes sixty seconds, it is right for fritters, and most other uncooked articles.
Use a deep frying-pan or kettle. A wire frying-basket to hold the articles to be fried, hung on a long-handled fork, is convenient; but they may be lowered into the fat and taken from it with a spoon-shaped wire egg-beater. Put the fat into a cold kettle, and bring it slowly to the right degree of heat. Have ready several sheets of soft paper laid on a pan, also a pan to hold under the food as it is taken from the fat. Test the fat; if right, dip the basket or wire spoon into the fat to heat and grease it. If a basket is used, lay three or four articles in it, and lower them till the fat covers them. When they are a delicate golden brown, lift the basket, shake it a little, and let the food drain for a moment before removing it to the paper. Reheat the fat, testing again if necessary, and fry another batch of articles. Three croquettes can be fried at once in a three-quart saucepan; more will cool the fat below the "soaking-point." When all grease has been absorbed by the paper, arrange the food on a platter, and garnish it with parsley; in the case of fish or oysters, with parsley and slices of lemon.