Experiment 7

To determine the factors which influence the rate of crystallization of sucrose and the size of the crystals.

Dissolve 1 cup of sucrose (200 grams) in 1/2 cup of water. (Increase or decrease these proportions if necessary.) Use pans of the same size and shape. Be sure the pans are smooth. Because the sirup splashed on the sides dries less readily from the heat of the burner, a pan with a straight side or one that curves in at the top is preferable to one that slopes outward at the top. If desired the sirup may be poured into plates for cooling instead of following directions under the outline. If this is done the containers into which it is poured should be smooth and the same size and all should be cooled in the same manner. Great care should also be taken to pour the sirup rapidly and not to scrape the pan.

If the amount of water in the fondant is to be determined, the pan and the stirring spoon should be weighed before the fondant is cooked. The weight of the fondant, before removal from the cooking pan, minus the weight of the sugar used gives the amount of water in the fondant.

A. Temperature at which the sirup is beaten.

1. Cook the sirup covered for 4 or 5 minutes. Remove the lid and continue boiling until sufficiently concentrated. (Cook to 113°C. if the day is clear, and to 114° or 115°C. if rainy or if the humidity is high.)

Boil the sirup without stirring or if stirred follow the caution given in the text. Cool the sirup in the sauce pan to 40°C. then beat until stiff. If a wooden spoon is used for beating it is less likely to form blisters on the hands than a metal spoon. After crystallization has occurred, knead until soft. Care should be taken that no crystals form on the side of the pan during cooking or cooling, for they will seed the mass and the time for beating will thus be shorter for A2 and A3 than would normally be required and the crystals larger.

2. Repeat 1 but cool only to 70°C. before beating.

3. Repeat 1 but beat the sirup as soon as it is removed from the stove.

Examine portions of each fondant under the microscope. Wrap portions from each experiment in oiled paper and put away in a tightly covered container until the next lesson. What is the effect of 24 hours' storage on the firmness and the texture of the fondant? Why do the directions under Al state not to stir the sirup while cooking?

Temperature cooked to

Temperature cooled to

Time required to beat to crystallize

Size of crystals

Results and conclusions.

B. Concentration to which the sirup is cooked.

Repeat Al, but cook the sirup to 111°C. Compare the length of time required to beat to crystallize with that for A3.

C. Effect of added substances.

1. Repeat Al, but add 1 tablespoon of butter to the sugar and water. Follow directions under Al.

2. Repeat Al, but add 1/4 teaspoon of cream of tartar to the recipe. The proportion of cream of tartar may need to be varied somewhat with the hardness of the water, but the rate of cooking will have more effect than the hardness of the water. Boil over a large gas burner so that the time of cooking does not exceed 10 to 12 minutes. Follow directions under Al.

3. Repeat C2, but cook slowly, taking at least 2 or 3 times as long to cook as for C2.

4. Repeat Al, but add 1 teaspoon of cream of tartar to the recipe.

5. Repeat Al, adding 1 tablespoon of corn sirup to the recipe.

6. Repeat Al, adding 4 tablespoons of corn sirup to the recipe.

7. Melt 4 tablespoons of sugar. Stir while melting. Do not have the heat intense enough to decidedly darken or scorch the sirup. When it is all melted and a golden brown color, add boiling water and stir until dissolved. Then add to the fondant recipe and follow directions under CI.

Sugar grams

Water grams

Added substance

Cook to °C.

Cool to °C.

Time required to cook to reach


Time required to beat to crystallize

Amount of water in fondant





If C4, 6, and 7 do not crystallize let them stand until the next lesson. What would be the effect on the rate of crystallization if these candies were allowed to cook to a higher temperature? If they were beaten hot? What is the effect on the rate of crystallization of sugar when considerable hydrolysis has occurred, as in C3 and C4, or when a large amount of corn sirup or caramelized sugar has been added, as in C6 or C7?

Test portions of Al and C2 with Fehling's solution.

What is the action of cream of tartar when added to fondant? What would be the result if vinegar or lemon juice were substituted for the cream of tartar in C2 and C3? Is the fondant obtained in C2 and C3 superior to that obtained in Al ? Compare the keeping qualities of the different fondants by putting some of each away in a covered container and observing at different periods. Examine portions of each under the microscope.

Experiment 8

To determine the comparative ease of crystallization of different sugars in making fondant.

A. Repeat Experiment 7A, but substitute dextrose for the sucrose.

B. Repeat Experiment 7A, substituting levulose for the sucrose. If levu-lose cannot be obtained use honey, which contains a high percentage of levulose. Or use the liquid portion of crystallized honey, which is nearly pure levulose.

If any under A or B do not crystallize, recook them. See if they will crystallize after being cooked to a higher temperature.


Experiment 9

To determine the factors influencing the consistency and flavor of fudge. Recipe:

Sugar Milk Butter Chocolate

1 cup 1/2 cup 1 tablespoon 3/4 square

200 grams

122 grams

14 grams

21 grams

Combine sugar, chocolate, butter, and liquid. Stir until the sugar is dissolved and the chocolate is melted. Cook to the temperatures given below. If the mixture is poured into another container for cooling, be sure the container is smooth. If it is poured into a platter or similar utensil, cooling will be more rapid and even more so if the platter is set on a cake rack or is elevated. Use containers of the same size and the same method for all the experiments. Cool to 40°C. and beat until the mass begins to crystallize. Turn quickly into a buttered pan or knead as desired. Select thermometers that have the same boiling point. The recipe may need to be doubled or increased so that the quantity of material in the cooking pan will be great enough to cover the bulb of the thermometer in order to obtain an accurate reading. How should the thermometers be held in the sirup to determine differences in consistency of the finished fudge, when the difference in temperature to which the sirup is cooked is only 1 degree?