(1) Place one test-tube in warm water and heat to boiling.
(2) Place one test-tube in water which feels warm to the hand.
(3) Place one test-tube in cracked ice and freeze the mixture. Afterwards thaw, and place the same test-tube in lukewarm water.
Observe the results, and compare the amount of gas formed under the different conditions.
LESSON II
PRACTICAL BREAD-MAKING
Ingredients of plain bread:
1. Liquid.—(1) It wets the mixture and causes the ingredients to adhere.
(2) It furnishes steam for a lightening gent.
(3) It allows the gluten to become sticky and elastic.
(4) It furnishes moisture for yeast plants.
2. Yeast.—It gives off carbonic acid gas, which lightens the mixture.
3. Salt.—(1) It gives a flavour.
(2) It retards the growth of the yeast plant.
4. Flour.—(1) It thickens the mixture.
(2) It supplies food for the yeast plant.
(3) It supplies gluten for a framework for the mixture.
Amount of ingredients for one small loaf:
Liquid—1 cup or 1/2 pt.
Salt—1/2 tsp.
Flour—About three times the amount of liquid
Yeast—Amount depends on the time given the bread to rise, as follows: