Experiment 89

To determine the smoking temperatures of different fats.

Use, preferably, evaporating dishes or small sauce pans of the same size. Have the fat come to within 1 inch of the top of the dish. Heat the fat slowly. When you see the first puff of smoke, record the temperature of the fat. Cool and take the smoking temperature a second time. Compare the smoking temperature of olive oil, cottonseed oil, peanut oil, corn oil, fresh hydrogenated fat, lard, used lard, and used hydrogenated fat.

Kind of fat

Smoking temperature

Experiment 90

To determine the factors which may cause variations in the smoking temperature of the same fat.

1. Take the temperature of used hydrogenated fat or used lard in a large kettle. Compare with the smoking temperature of used hydrogenated fat or used lard in the small dish under Experiment 89.

2. Take the smoking temperature of hydrogenated fat to which 1 tablespoon of flour has been added. Compare with the smoking temperature of hydro-genated fat under Experiment 89.

Smoking temperature

Experiment 91

Household tests for determining the temperature of fats.

Find the temperature of a fat when a cube of dry bread browns in 60 seconds; in 40 seconds; in 20 seconds.

Make the first test when the fat is at 170°C. (340°F.). Which temperature is said to be used for cooking raw foods? For browning cooked foods?



Experiment 92

To determine the temperature at which foods actually cook.

Use potatoes sliced and cut into strips, and croquettes. When the fat has reached the temperature which has been decided as best for cooking raw foods under Experiment 91, immerse the food in the fat. Watch the temperature of the fat as the food cooks. Note also the time required to brown the food. Do you think as a result of this experiment that heating a fat to its smoking temperature always gives a desirable temperature for cooking foods?

Kind of food

Tempera-ture of fat

Tempera-ture of fat during cooking

Length of time to cook

Fat absorbed


Per cent

Experiment 93

To determine the tendency of fats to retain the flavor of food that has been cooked in the fat.

Use hydrogenated fat, cottonseed oil, lard, or other fat or oil. Cook fish or onions in the fats, then potato cut in strips. Cook croquettes also. Do the potato and croquettes taste of fish or onions?

Doughnuts Experiment 94.

To determine the factors which influence the tenderness, the texture, and the amount of fat absorbed in doughnuts. Recipe:

Flour 51/4 cups

588 grams or use the amount found best under A

Baking powder








2 tablespoons 1 teaspoon

1 cup

2 tablespoons 2

1 cup

1/8 teaspoon

1/8 teaspoon

21 grams 4 grams

200 grams 25 grams 96 grams

244 grams

It is more convenient to work in groups of five or six girls for the doughnut experiments. It will take two girls to fry the doughnuts; one to watch the temperature, one to time, to put the doughnuts in, turn, and take them out of the fat. Or a third girl may time the cooking. One girl should do all the mixing, doing it in the same way each time and with the number of strokes designated under each experiment. Another girl should do all the rolling and cutting, handling each batch in the same way and trying not to stretch or pull the cut dough out of shape. Other girls may weigh the materials. The eggs should be beaten together for all the experiments to be done by the group in one period. It is best not to use the results of the first mixing for comparisons but to use them for obtaining technic in handling the dough in mixing, cutting, and cooking.

Directions for mixing.

Remove the flour for rolling before the baking powder is added to it. Sift the flour and baking powder together 2 times. Combine the thoroughly beaten eggs, sugar, salt, and softened or melted fat, mixing until very light and fluffy. Use the same kind and size of bowl for mixing the materials for each experiment. Add the milk and flour to the other ingredients and mix the designated amount.

Roll the dough between boards 1/4 or 3/8inch in thickness, tacked to a bread board, so that all the doughnuts will be the same thickness. Each group should use cutters that have the same diameter. If the dough is divided into 2 parts and each half rolled in part of the flour and shaped into a long roll before placing between the boards it facilitates ease of handling. There should be 3 doughnuts from each part of the dough and 6 for each experiment.

In cooking, the doughnuts should be turned when half of the time allowed for cooking is gone. When the time is up, lift each doughnut quickly from the fat onto a skewer held over the kettle so that the fat will drain back into the kettle. The doughnuts should be turned and taken out in the same order they are put into the fat.

Weigh the kettle of fat before and after cooking the doughnuts for each experiment. The loss of weight of kettle of fat is the amount of fat absorbed by the doughnuts. Weigh the doughnuts before and after cooking if the percentage of fat absorbed is to be calculated. The percentage of fat in the cooked doughnuts may be determined by analysis, but this requires too long a time for class results. The percentage of fat absorbed may be based on the weight of the cooked doughnuts or on the weight of the uncooked doughnuts. Denton has suggested that the former is preferable, and this method has been used in calculating the results given in the tables.

A. To determine the best proportion of flour to use.

The proportion of flour to produce a tender doughnut of good texture varies with different brands and kinds of flour. Therefore, it will be necessary to determine the best proportion for the kind and brand that you use; this proportion is to be used in the following experiments. With some flours it will be necessary to start with 5 3/4 cups or 6 cups of flour instead of 5 1/2 cups. The dough should be soft and light but not too sticky. If desired, two series of experiments may be run, using bread flour in one and soft-wheat flour in the other.