Foods and home making

What are some points to consider in buying bread? Bread is sold with and without paper wrapping. Which shall we buy ? Bread wrapped in paper costs more than the unwrapped. It is, of course, cleaner and freer from bacteria than that which is uncovered. Since bread is most often eaten without being heated or cooked, it pays to buy the wrapped loaves, even though they cost more. Wrapping bread in paper also keeps it fresher. Loaves of bread vary greatly in size. If loaves of different weight are sold, it is well to weigh them and determine the cost by the ounce. For example, a loaf of bread weighing 14 ounces and selling for 12 cents would cost (12 -4- 14) .85+ cent an ounce. Another loaf weighing 5 ounces and costing 6 cents would cost 1.2 cents an ounce. If all the larger loaf could be eaten, it would be the better buy. 1 See page 17 of Food, Nutrition, and Health by McCollum and Simmonds. Yeast Breads 425 The quality of the bread needs, of course, to be taken into consideration. This is a difficult matter if we do not know what ingredients were used in making the bread. The bread can be scored as explained on page 430, to judge its quality. How does yeast make breads light ? We learned that baking powder forms a gas which makes dough porous and light. A gas is formed also when yeast is used to leaven bread. However, forming gas by the action of yeast is very different from form- ing gas by the action of baking powder. Baking powder is a white dry powder. Yeast is sold at mar- ket in cakes. The cakes may be either dry or moist. Moist yeast cakes are called compressed yeast. From the action of this kind of yeast, gas may be formed more quickly than from dry yeast. For this reason, we shall use compressed yeast in experimenting. Experiment 27: To learn how to use yeast. (a) In a cup mix 1 tablespoon flour, 1 tablespoon sugar, and 5 table- spoons cold water. Break 1 cake of compressed yeast into bits and add it to the flour mixture. Stir. Put 1 teaspoon of this yeast mixture into a test tube. Fill the tube nearly full with lukewarm water. As you have already learned, if gas is forming, bubbles will appear at the surface of the liquid. Do you see any bubbles? (b) Surround the tube with lukewarm water. Set it aside in a warm place for at least 15 minutes. Do you now see any bubbles in the test tube ? The gas that is formed in the test tube is carbon dioxide. The pasty cake of yeast which you used was filled with plants. Of course, you could not see the plants in the yeast cake because they were so tiny. Then, too, yeast plants are not green. They do not have leaves and roots. They do not look like the plants which you find in the garden. Like other plants, yeast plants need soil or food on which to grow. The flour and sugar served as food for the yeast plants. Yeast plants also need moisture and heat to make them grow. The warm water furnished the plant with moisture and heat. 426 Dinner Yeast plants grow rapidly. (See Figure 128.) As yeasts grow, they break up the food needed for growth. From the food, the gas, carbon dioxide, and alcohol are formed. When yeasts are grow- ing in bread dough, the carbon dioxide which is formed makes the dough porous. The alcohol passes off as a gas when the dough is baked. The yeast plants are destroyed by baking.