This section is from the book "Experimental Cookery From The Chemical And Physical Standpoint", by Belle Lowe. Also available from Amazon: Experimental cookery.
To determine the best proportions of ice and salt to use in freezing an ice. Recipe:
Water Sugar Lemon juice
1 cup 1/2 cup
Dissolve the sugar in the water and bring to the boiling point. Cool to 30°C. and add the lemon juice, then freeze. Turn the freezer slowly at first, then rapidly or use an electric freezer. Try each of the following proportions of salt and ice. See freezing directions, Experiment 12. Compare the consistency of the frozen ices, the fineness of the crystals, and the flavor. Compare the swell obtained with the different proportions of ice and salt.
1. Use 1 part of salt to 3 of ice.
2. Use 1 part of salt to 6 of ice.
3. Use 1 part of salt to 8 of ice.
4. Use 1 part of salt to 12 of ice.
What is the proportion of ice and salt given in cook books as best for freezing ices? Are your results in accordance with these proportions? Are the best proportions for an ice and for an ice cream the same?
What would be the effect of adding a larger proportion of sugar to the recipe? If you wish to add whole strawberries or other fruit to a frozen dessert, how would you treat them to prevent their freezing into chunks of ice?
To determine the effect of the rate of turning the freezer upon the texture of an ice.
Use the proportions of salt found best in Experiment 14. See Experiment 12 for freezing directions.
Notice when the ice begins to turn white. When does the swell begin? Compare the texture of the finished products.
1. Turn slowly all the time, about 40 turns or less per minute.
2. Turn slowly at first, 40 turns or less per minute; then rapidly while freezing, about 100 turns per minute.
3. Turn rapidly all the time, about 100 turns per minute.
4. If you have a vacuum freezer use it for one lot, or freeze one lot in the mechanical refrigerator.
To determine the effect on the texture of an ice when a binder is added. Use 1 part of salt to 8 parts of ice or the best proportions found in Experiment 14. See Experiment 12 for freezing directions.
1. Prepare the lemon ice as given in the recipe for a control.
2. To the recipe given add 1/2 teaspoon of gelatin. Hydrate the gelatin by letting it stand a short time with 1 tablespoon of water. Then dissolve in the hot sirup.
3. To the half-frozen ice, add 1/2 egg white beaten stiff. Finish freezing.
4. Prepare lemon ice adding both 1/2 teaspoon of gelatin and 1/2 egg white beaten stiff. See 2 and 3 for directions for adding to the ice.
5. Pour the hot sirup over 1/2 egg white beaten stiff. Beat while adding the sirup. Cool, add lemon juice, and freeze.
6. Repeat 1, but do not make a sirup of the sugar and water. Dissolve the sugar in the cold water, add the lemon juice, and freeze.
7. Repeat 6, but substitute milk for the water.
Which mixtures give the best textures? Which are the easiest to prepare and freeze? Results.
Suggestions for Additional Experiments
To determine the effect on the texture of ice cream when a filler is used. Recipe:
Cream Sugar Milk Vanilla
3 tablespoons 1/4 cup 1/4 teaspoon
160 grams 37.5 grams 80 grams a. Add 3/4 tablespoon of flour (5.3 grams) to the recipe. Boil and cool before freezing.
b. Add 1/4 beaten egg (12 grams) to the recipe. Scald. Cool, then freeze. To find the effect of aging the cream. Use cream with the same percentage of fat, but have one lot 24 hours older than the other.
To find the effect of homogenizing the cream. Use cream of the same percentage of fat and the same age but have one lot homogenized, the other unhomogenized.