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 CX
LEAVENING WITH BAKING SODA AND SOUR MILK: SPIDER 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 67: 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 7)? What does this experiment teach with regard to the use of baking soda and sour milk, for lightening a mixture?
EXPERIMENT 68: CHEMICAL CHANGE.--Measure 1/4 cupful of thick sour milk.
[Footnote 78: The amount of acid in sour milk varies slightly.] 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 1/8 teaspoonful of baking soda. Mix this with 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 3/4 of the soda mixture, stir and heat until effervescence (bubbling) has ceased. Test the mixture in the saucepan with blue litmus paper. If the blue litmus 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, entirely different materials are formed; one is the neutral substance in the pan; another is the carbon dioxide gas which has escaped, and the third is water. 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 69: QUANt.i.tY OF BAKING SODA TO USE WITH SOUR MILK.--To the contents of the saucepan of Experiment 68, add 1/8 teaspoonful more of baking soda. Stir, heat, and test with pink litmus. What is the reaction-- acid or alkaline? Has the last quant.i.ty of soda been neutralized as was the first quant.i.ty? Explain.
If more baking soda than is necessary to neutralize the acid of the sour milk is used, some _unneutralized_ soda will remain in the mixture.
This is undesirable, since soda has a "bitter taste." An excessive quant.i.ty of unneutralized soda also discolors the mixture.
Experiments 68 and 69 indicate that the _approximate_ proportion of baking soda to sour milk is: _1/2 teaspoonful of baking soda to 1 cupful of thick sour milk._
The following "equations" indicate the importance of using the proper amount of baking soda to neutralize the acid materials:
1 cupful of sour milk + 1/2 teaspoonful of baking soda --> [Footnote 79: The plus sign is read "with"; the arrow is read "yields."] water + carbon dioxide gas + neutral material.
1 cupful of sour milk + 1 teaspoonful of baking soda --> water + carbon dioxide gas + neutral material + unneutralized "soda."
SPIDER CORN BREAD
3/4 cupful corn-meal 1/2 teaspoonful baking soda 1/4 cupful flour 1 egg 1 tablespoonful sugar 1 cupful sour milk 1/2 teaspoonful salt 1 tablespoonful b.u.t.ter or subst.i.tute
Mix the dry ingredients. In a mixing bowl, beat an egg, add the sour milk, then the dry ingredients. Beat the mixtures until the ingredients are well blended.
Melt the b.u.t.ter or subst.i.tute in a hot "spider" or frying pan. Pour the corn-meal mixture into it. Bake in a hot oven until sufficiently baked, usually about 20 minutes (see tests below). Serve hot.
TESTS FOR SUFFICIENT BAKING OF QUICK BREAD.--Quick Bread is usually sufficiently baked: (_a_) when it is a golden brown in color; (_b_) when the mixture shrinks from the pan; (_c_) when the crust springs back into place, if pressed gently with the fingers; or (_d_) when no batter or dough clings to a wire skewer or knitting needle (see Figure 1) that has been inserted. Usually it is not necessary to apply this last test, unless the quick bread is baked in a loaf or in a very thick layer.
QUESTIONS
Mention the materials used in Spider Corn Bread to make it light. Explain their action.
Explain why satisfactory results could not be obtained by using 1 1/2 teaspoonfuls of baking soda in this Spider Corn Bread recipe.
What is the price per half-pound of baking soda?
How many persons does this Spider Corn Bread recipe serve?
LESSON CXI
LEAVENING WITH BAKING SODA, SOUR MILK, AND MOLa.s.sES: GINGERBREAD
EXPERIMENT 70: ACTION OF BAKING SODA ON MOLa.s.sES.--Place a teaspoonful of baking mola.s.ses in a test tube and dilute with a little water. Test it with litmus paper. What is its reaction? Add a pinch of baking soda. Heat.
What does effervescence indicate? What do we call the gas formed by the action of the baking soda and a substance having an acid reaction? Explain how baking soda and mola.s.ses could be used to lighten a quick bread.
EXPERIMENT 71: QUANt.i.tY OF BAKING SODA TO USE WITH MOLa.s.sES.--Carefully measure 1/8 cupful of mola.s.ses. [Footnote 80: The acidity of mola.s.ses may be due to fermentation or to the preservatives used in many brands. Its intensity varies.] Dilute it with much water. Carefully measure 1/16 teaspoonful of baking soda and mix it with water. Add about 3/4 of the soda mixture to the mola.s.ses solution. Stir and heat. Test with blue litmus. If it changes color, keep adding the soda mixture, until the litmus paper does not change, as in Experiment 68. When neither blue nor pink litmus paper changes color, what kind of substance,--acid, alkaline, or neutral,--is present? What change has taken place in the materials placed in the saucepan?
This experiment shows that the _approximate_ proportion of baking soda to mola.s.ses is:
1/2 _teaspoonful of baking soda to_ 1 _cupful of mola.s.ses_.
This "equation" expresses the chemical change in the experiment:
1 cupful mola.s.ses + 1/2 teaspoonful of baking soda --> neutral material + carbon dioxide gas + water.
GINGERBREAD
2 cupfuls flour 1/2 teaspoonful salt 3/4 teaspoonful baking soda 1 teaspoonful cinnamon 2 teaspoonfuls ginger 1/8 teaspoonful cloves 1 egg 1 cupful thick sour milk 1/2 cupful mola.s.ses 1/2 cupful sugar 2 to 4 tablespoonfuls fat
Mix all the dry ingredients except the sugar. Beat the egg in a mixing bowl. Add the sour milk, mola.s.ses, and sugar. If solid fat is used, melt it. Add the fat to the mola.s.ses mixture. Through a sifter, add the dry ingredients to other materials. Beat thoroughly and turn at once into a shallow oiled pan. Bake in a moderate oven (375 degrees F. to 400 degrees F.) 20 minutes or longer (see _Tests for Sufficient Baking of Quick Bread_)
_Gingerbread without Eggs_ may be made. Omit the egg from the recipe above. To the dry ingredients, add 1 teaspoonful of baking powder.
_Water Gingerbread_ may be made by subst.i.tuting 7/8 cupful cold water for the sour milk, and using 1/4 teaspoonful baking soda (instead of 3/4 teaspoonful) and adding 3 teaspoonfuls of baking powder.
QUESTIONS
Mention the leavening materials used in this Gingerbread, and explain their action.
What is the price per quart of mola.s.ses?
How many persons does this recipe serve?