LESSON XXXIV
FAT AS A FRYING MEDIUM
COMPARISON OF FATS AND CARBOHYDRATES.—Fat is a foodstuff. Fat and oil [Footnote 38: Fat and oil are very similar, oil being fat that is liquid at ordinary temperature.] form another great class of energy-giving or fuel foods. In the body, these foods, like carbohydrates, give energy; in fact weight for weight they furnish more than twice as much energy as carbohydrates. There is, for example, about as much fat by weight in one pound of butter as there are carbohydrates in one pound of tapioca. By measurement it has been found that one pound of butter gives to the body almost two and one fourth times as much energy as does one pound of tapioca.
Fats and oils are not only used as food (butter for example) and as constituents of foods (fat in pastry), but as a medium for cooking. The use of fat as a cooking medium follows:
EXPERIMENT 31: TEMPERATURE AT WHICH FATS AND OILS DECOMPOSE OR "BURN."— Into each of 6 test tubes put 2 teaspoonfuls of butter, cottonseed oil, corn oil, beef drippings, lard, and Crisco. Gently heat each one of the fats or oils until fumes first arise from them. Then insert a thermometer [Footnote 39: Care should be taken in using a thermometer in hot fat. It should be allowed to cool before washing.] in each tube and note the temperatures. These are the temperatures at which the various fats decompose. Record these temperatures in your notebook.
How do the decomposing temperatures of fat compare with that of boiling water? Which would be the hotter medium for cooking—hot fat or boiling water?
Which fat reaches the highest temperature before it begins to decompose? If fat is used as a medium of cooking, which of these fats, as far as temperature is concerned, would be the most desirable? Give a reason for your answer.
What is the price per pound or pint of each of these fats or oils?
Which of these are vegetable and which are animal fats or oils?
FATS FOR DEEP-FAT FRYING.—As shown by the above experiment, fat reaches a high temperature when heated. For this reason fat may be used as a cooking medium. The process of cooking food in deep fat is called frying. From the standpoint of temperature the best fat for frying is that which can be heated to a very high temperature without burning.
Other factors such as flavor and cost, however, have to be taken into consideration. Fat not only heats foods, but it imparts flavor since some of the fat in which a food is cooked, clings to the food. The costs of the various fats differ greatly. This must be regarded in selecting fats for cooking. Taking these factors into consideration, many prefer the cheaper vegetable fats for frying, while others find a mixture of beef drippings and lard satisfactory.
EXPERIMENT 32: BREAD FRIED IN "COOL" FAT (CLASS EXPERIMENT).—Put some suitable fat for frying in an iron pan and heat. Note carefully the change that takes place in fat as it heats. When the fat "foams" or bubbles, or reaches a temperature of about 300 degrees F., drop into it a piece of bread. After one minute remove the bread from the fat; examine the bread by breaking it apart to see if the fat has soaked into the bread. Is it desirable to have the fat soak into fried foods? What conclusion can you draw as to frying foods in "cool" fats?
EXPERIMENT 33: THE TEMPERATURE OF FAT FOR FRYING (CLASS EXPERIMENT).— Continue to heat the fat of Experiment 32. When fumes begin to rise from the fat, or the fat reaches a temperature of 365 degrees F., again drop a bit of bread into it. After one minute remove the bread and examine it as above. Has as much fat soaked into it as in the first bit of bread? What conclusion can you draw from this in regard to the proper temperature for frying foods?
Cooked foods and foods needing but little cooking require a higher temperature than batters or other uncooked foods. If a bit of bread is browned in 40 seconds, the fat is of proper temperature for cooked foods and for oysters. If bread is browned in 60 seconds, the fat is of proper temperature for uncooked foods.
GENERAL RULES FOR FRYING.—Since fat, when heated, reaches such a high temperature, the kettle in which it is heated should be of iron.
If there is any moisture on foods, it must be evaporated before the foods brown. Excessive moisture also cools the fat considerably, hence, foods that are to be fried should be as dry as possible.
Place the foods to be cooked in a bath of fat deep enough to float them. The kettle should not be too full, however, as fat is apt to bubble over especially when moist foods are placed in it.
Foods may be placed in a frying basket, or they may be lowered into the fat and taken from it with a wire spoon. All fried foods should be drained on paper.
When one quantity of food has been removed, the fat should be reheated and its temperature tested before adding the second quantity of food.
Fat used for frying should be cooled and clarified with potato as directed on the following page.
If a coal range is used for heating the fat, sand or ashes and a shovel should be near at hand in case the fat takes fire.
If hot fat must be carried or lifted, wrap a towel about the hand before grasping the handle of the kettle.
TO TRY OUT FAT.—The fat of meat consists of fat held by a network of connective tissue. To make meat fat suitable for frying it is necessary to separate the fat from the tissue. This is done as follows:
Remove the tough outside skin and lean parts from meat fat and cut it into small pieces. Put the fat into an iron kettle, and cover it with cold water. Place it uncovered on the stove and heat. When the water has nearly all evaporated, set the kettle back, or lessen the heat, or place in a "cool" oven, and let the fat slowly try out.
As the fat separates from the pieces of tissue, it is well to strain or drain it into a bowl. If this is done, the fat is less apt to scorch. The heating of the connective tissue should continue, until it is shriveled in appearance and no fat can be pressed out from it with a fork. The strained fat should be set aside to become firm and then stored in a cool place.
TO CLARIFY FAT.—Add a few slices of raw potato to fat and heat slowly until it ceases to bubble. Cool, strain through a cloth, and let stand until solid.
FRIED OYSTERS [Footnote 40: NOTE TO THE TEACHER.—If the price of oysters is too high, some seasonable small fresh fish such as pike may be used in place of oysters. These may be prepared for frying in the same manner as oysters. If desired, corn-meal may be substituted for dried bread crumbs.]
Large oysters
Dried bread crumbs
Salt and pepper
Eggs
1 tablespoonful water or oyster juice for each egg
Remove pieces of shell from the oyster by running each oyster through the fingers. Wash the oysters, drain immediately, and dry them on a soft cloth or towel (see Cleaning Oysters). Season with salt and pepper. Beat the eggs slightly and dilute by adding one tablespoonful of water or strained oyster juice to each egg. Sprinkle salt and pepper over the dried bread crumbs. Dip the oysters into the prepared crumbs, then into the egg mixture, and finally into the crumbs. Fry one minute, drain, place on paper, and serve.
Lemons cut into eighths are desirable to serve with fried oysters. Parsley makes a pleasing garnish.
To Clean Utensils that have Contained Fat.—An alkaline substance such as washing soda is effective in cleaning utensils that have held fat. To show the action of washing soda on fats try the following:
EXPERIMENT 34: SAPONIFICATION OF FAT.—Into a test tube put 1/2 teaspoonful of washing soda and 1 teaspoonful water, then heat until the washing soda is entirely dissolved. Melt 1 teaspoonful of solid fat and add it to the soda solution. Boil the contents of the tube for a few minutes and then examine it. What substance does the foaming suggest? What has been formed by the union of fat and soda? What application can be drawn from this with regard to the use of soda in cleaning utensils that have contained fat?
Wipe out with soft paper the utensil that has held fat. Fill it full of water, add some washing soda, and heat. Empty the water and wash. Do not use washing soda in aluminum utensils (see Preparing Dishes for Washing).