Experiments With Leavens And Leavening

AGENTS Egg, air, steam

169. - Measure the unbeaten white of an egg in a tablespoon. Beat with a Dover egg beater and measure in a tablespoon. Result?

170. - Whip an unbeaten egg white with a wire whisk. What is the difference in volume? To what is this due? Notice the difference in size of air spaces where Dover beater is used as compared with wire whisk.

171. - Perform 169 and 170 each with an egg yolk. Why is the increase in volume less noticeable?

What is the marked difference in the composition of the egg yolk as compared with the egg white?

172. - a. Use the unbeaten egg to make popovers.

b. Use the beaten egg to make sponge cake.

c. Use the whipped egg to make Foamy Omelet. Compare texture of each product. Explain.

d. Which egg white at time of using contains most water?

Sodium bicarbonate

173. - Have ready for this and the succeeding experiments, the following: baking soda cream of tartar lemon juice vinegar sour milk molasses chocolate coffee hot water tomato limewater

Test with litmus and record reaction of each.

174. - Carbon dioxide precipitates the lime in a solution of lime and water. This can be shown by breathing through a tube, one end of which is immersed in a beaker of limewater. The white, chalky deposit which soon appears on the bottom of the beaker is carbonate of lime from the lime of solution and the carbon dioxide of the breath.

175. - Arrange 9 test tubes with perforated corks or rubber stoppers fitted with a bent tube to conduct gas from test tube into beaker of limewater.

In each dry test tube put 1/4 tsp. dry baking soda. Arrange perforated corks or stoppers with bent tube and have ready to adjust at once and conduct the gas given off into limewater (equal volume in each beaker).

When all is ready, put 1 tbsp. of an acid or hot water respectively into a test tube until all have been used. Several phenomena will be observed.

Note the evolution of gas, rapidity with which given off, comparative amount of carbonate of lime deposited. Conclude the corresponding amount of carbon dioxide given off.

Tabulate and compare the results.

176. - If the facilities of the chemical laboratory are available, make the experiment with cream of tartar quantitatively, using pure substances.

177. - In the experiment with cream of tartar, it will be necessary to add water before the action will take place.

What does this explain in regard to baking powder ? Why is corn starch or flour used in the manufacture of baking powder ?

178. - Test 1/4 tsp. of baking powder with 1 tbsp. hot water. Assuming that the baking powder is a mixture of sodium bicarbonate and an acid salt, can you determine the nature of the latter by chemical analysis ?

179. Prepare baking powder according to the following proportion :

1/2 lb. cream tartar 1/4 lb. baking soda 1/4 lb. corn starch Sift six times