A text-book of cooking

Pour Batter. — All breads may be divided into two classes: (a) Quick Breads and (b) Yeast Breads. The former are so named because a much shorter time is required in their preparation. Quick breads are divided into several classes, depending upon the proportion of flour and moisture in the batter. A pour batter is the thinnest quick bread mixture. It usually contains about equal parts of flour and moisture. A definite proportion cannot be stated, since the thickening quality of different flours varies, and the wetting quality of different moist materials varies. Many pour batters contain a little more flour than moisture. Popover mixture is a typical pour batter. What change, other than moistening the flour, takes place in the milk that helps to lighten the Popovers ? What changes take place in the eggs and in the air inclosed in them when they are heated quickly ? ' What is the purpose of beating the Popover mixture thoroughly ? How many Popovers will the given recipe make ? LESSON LXIV Leavening with Baking Soda and Sour Milk: Corn Bread Besides the air that is beaten into the eggs and into the combined ingredients of quick bread mixtures, a gas — carbon dioxide — is often introduced into such mixtures. To find how this gas may be formed, try the following : Experiment 69: Action of Baking Soda on Sour Milk. — Place a teaspoonful of sour milk in a test tube and add a pinch of baking soda. Do you notice any change in the ingredients ? Apply heat to the contents of the tube. What kind of material (solid, liquid, or gas) is indicated by the bubbling ? (See Experiment 62, p. 176.) What does this experiment teach with regard to the use of baking soda and sour milk, for lightening a mixture ? Experiment 70: Chemical Change. — Measure \ cupful of sour milk. 1 Dip the end of a piece of blue litmus paper in it. What change in color takes place in ■ the paper ? When blue litmus changes to pink, an acid is present. The sour milk therefore contains acid. Measure J teaspoonful of baking soda. Dissolve this in a little water. Test with pink litmus paper. When pink litmus paper changes to blue, an alkaline substance is present. Baking soda is therefore alkaline in reaction. Pour the milk into a saucepan, add about f of the dissolved soda. Stir and heat until effervescence (bubbling) has ceased. Test the mixture in the saucepan with blue litmus paper. If the blue litmus 1 The amount of acid in sour milk varies slightly. paper changes color, carefully add a little more of the soda solution. Test with litmus again. If there is still a change in color, add soda solution until the litmus does not change. Then test with pink litmus. When neither pink nor blue litmus paper changes color a neutral substance is present, i.e. a substance neither acid nor alkaline. When this occurs, the mixture in the pan is no longer acid in reaction. Neither sour milk nor baking soda exists in the pan. A chemical change has taken place. From the union of sour milk and soda, two entirely different materials are formed ; one is the neutral substance in the pan; the other is the carbon dioxide gas which has escaped. When an acid and an alkaline material are mixed, a chemical change always occurs. Chemical changes are constantly taking place when certain food mixtures are cooked and digested. Experiment 71 : Quantity of Baking Soda to Use with Sour Milk. — To the contents of the saucepan of Experiment 70, add \ teaspoonful more of baking soda. Stir, heat, and test with pink litmus. What is the reaction — acid or alkaline? Has the last quantity of soda been neutralized as was the first quantity? Explain your answer.