EXPERIMENT 72: EFFECT OF COLD WATER ON A MIXTURE OF CREAM OF TARTAR AND
BAKING SODA.—Test a bit of cream of tartar with moistened litmus paper.
Is it acid or alkaline in reaction?

Put 1/8 teaspoonful of baking soda and twice the quantity of cream of tartar in a dry test tube. Does any change take place? Add about 1 teaspoonful of cold water to the mixture and examine. What change takes place? What substance is being formed?

EXPERIMENT 73: EFFECT OF HOT WATER ON A MIXTURE OF CREAM OF TARTAR AND BAKING SODA.—Repeat Experiment 72, using hot water instead of cold with the baking soda and cream of tartar. Which causes greater effervescence,— hot or cold water? Is it desirable to have more of the gas formed before or after the mixture is placed in the oven? What, then, should be the temperature (hot or cold) of liquids and other materials used in the quick bread mixtures?

EXPERIMENT 74: EFFECT OF HOT WATER ON BAKING POWDER.—Add about 1 teaspoonful of hot water to 1/4 teaspoonful of baking powder. Compare the effervescence with that of Experiment 73. From the comparison of Experiments 72 and 73, with Experiment 74, what two kinds of substances do you infer this baking powder contains?

(Save the contents of the tube for the following experiment.)

EXPERIMENT 75: STARCH IN BAKING POWDER.—Filter the contents of the tube used in Experiment 74 through filter paper (see Figure 30). Add a drop of tincture of iodine to the insoluble material left on the filter paper. What is the insoluble constituent of this baking powder?

COMPOSITION OF BAKING POWDER.—Baking powder consists of

(a) baking soda, (b) a substance having an acid reaction, (c) a starchy material.

The substance of acid reaction varies in different baking powders. Some powders in common use contain either cream of tartar, calcium or sodium acid phosphate, or alum [Footnote 81: Alums differ in composition. They are sulphates of various metals. The alum most commonly used in alum baking powder is sodium aluminium sulphate.] as the "acid" material. Certain baking powders contain a mixture of materials with acid reaction, such as cream of tartar with tartaric acid, and alum with calcium acid phosphate.

The starch is added to keep the other materials apart, and thus prevent the possible formation and consequent loss of carbon dioxide.

The trade name of a baking powder does not usually suggest its composition. But the latter is always stated on the label of the can.

EXPERIMENT 76: COMPARISON OF THE TIME OF ACTION OF DIFFERENT TYPES OF BAKING POWDERS.—Put 1/2 cupful of water of the same temperature into each of 3 tumblers or glass measuring cups. To one tumbler add 1/2 teaspoonful of tartrate baking powder; to the second, the same quantity of phosphate baking powder; and to the third an equal quantity of alum (or alum and phosphate) baking powder. Stir each and note the length of time that chemical change occurs in each tumbler. Which type of baking powder reacts the longest time?

DIFFERENCE IN TYPES OF BAKING POWDERS.—Although there has been much discussion regarding the superiority of one type of baking powder over another, it is thought that one standard baking powder is as little harmful as another. But, as shown by Experiment 76, the action of certain types is slower than that of others, i.e. the formation of the gas continues for a longer time. Certain types of baking powders which react very quickly when moisture is added may react to some extent while still in the can and thus lose some of their effectiveness in leavening. It is well to buy those baking powders in such quantities so that a fresh can can be purchased often. The price of certain types of baking powders is much greater than that of others.

QUANTITY OF BAKING POWDER IN QUICK BREADS.—Since baking powder contains both acid and alkaline materials, the quantity of baking powder used in a quick bread is dependent not upon another leavening material, but upon the quantity of flour and eggs. When no eggs are used, 2 tea-spoonfuls of baking powder should be used with 1 cupful of flour. When eggs are added to a quick bread, the quantity of baking powder should be lessened 1/2 teaspoonful for each egg.

Two and one half teaspoonfuls of baking powder should be used with 1 cupful of coarse wheat flour or flour or meal other than wheat.

SUGGESTIONS FOR PREPARING GRIDDLE CAKES.—The general rules for mixing quick breads apply also to griddle cakes. When the yolk and white of the egg are separated, the mixture will be somewhat lighter. Most housekeepers, however, beat the eggs together quickly, and find the result satisfactory.

The consistency of griddle cake batter is most important. As suggested in the recipe, the moisture should be added cautiously. Since the quantity of baking powder depends upon the amount of flour, it is better to change from a thick to a thinner batter by increasing the moisture, rather than to change from a thin to a thicker batter by increasing the flour. After mixing the batter, drop a small cake on the hot iron. The thickness as well as the grain of the browned cake depends largely upon the consistency of the batter. If too much moisture has been used, the cake is thin, "pasty," and coarse grained.

A griddle should be heated slowly, and should be hot when the cakes are mixed. If sufficient fat is used in the batter, it is not necessary to oil the griddle. The recipes for griddle cakes given in this book contain one and one half times the quantity of fat generally used in griddle cake batters. Hence oiling the griddle is unnecessary. It is well after each baking to wipe off the griddle with a cloth or paper.

Drop the batter by the spoonful (from the end of the spoon) on the hot griddle, brown on the under side thoroughly. When the cakes have risen, when the tops are full of bubbles, and when the edges are brown, the cakes should be turned and browned on the other side. Serve cakes at once after baking.

PLAIN GRIDDLE CAKES

2 cupfuls flour 1 egg 1/2 teaspoonful salt 1 1/2 cupfuls milk 3 1/2 teaspoonfuls baking powder 3 tablespoonfuls fat

Prepare according to the directions above. Add the milk cautiously. More or less (according to the absorbing property of the flour) than the given quantity may be required.

1/8 cupful of sugar or molasses may be added to the mixture. If desired, one more egg may be used in this recipe. Serve with maple or other sirup (see Sirup).

BREAD GRIDDLE CAKES

1 1/2 cupfuls bread crumbs 1 1/2 cupfuls hot milk 3 tablespoonfuls fat 1 to 2 eggs 1/2 cupful flour 1/2 teaspoonful salt 3 teaspoonfuls baking powder

Soak the bread in the hot milk until soft. Add the other ingredients in the order given.

1 cupful of cooked cereal may be used instead of bread crumbs. Rice Griddle Cakes are especially pleasing.

QUESTIONS

Account for the quantity of baking powder used in each of these recipes.

What is the price per pound of cream of tartar? Of tartrate baking powder? Of phosphate baking powder? Of alum baking powder? Of alum-phosphate baking powder?

What would be the effect of exposing baking powder to moist air? How should baking powder be stored?

What kind of griddle cakes result when the batter is too thin? When too thick?

What indicates that the griddle is too hot? Too cool?

How should griddle cakes be served?