Ii8 PURE FOOD IN THE HOME 



to form a thick paste. Add a little yeast which has been mixed with 

 lukewarm water. Divide this into three parts. Keep the first of 

 these at a temperature of 85 to 90 degrees, the second in a cold tem- 

 perature, and the third at the room temperature, say about 70 degrees, 

 for several hours. Then bake the three samples. 



Observation: Compare the three lots for appearance, texture, and taste. 



Conclusion: How do you account for the pores in the bread? What 

 caused the bread to rise? Under what conditions does the rising take 

 place best? 



Bread making. Most of us are familiar with the pro- 

 cess of bread making. The materials used are flour, milk 

 or water or both, salt, some butter or lard, a little sugar 

 and yeast. The sugar hastens the process of fermenta- 

 tion, or " rising," as it is called. After mixing the mate- 

 rials thoroughly, the dough is put in a warm place (about 

 75 Fahrenheit) to "rise." If we examine the dough after 

 some hours, we find it filled with holes, which give the mass 

 a spongy appearance. The yeast plants, owing to favorable 

 conditions, have grown rapidly and made the cavities with 

 carbon dioxide. Alcohol is present, too, but this is evapo- 

 rated when the dough is baked. The baking cooks the 

 starch of the bread, drives off both the carbon dioxide and 

 alcohol, and kills the yeast plants, besides forming a crust 

 on the loaf. 



Molds in the home. One of the most common enemies 

 of food in the home is mold. If you place two pieces of 

 bread, one kept moist, and the other dry, side by side in 

 the kitchen or living room, the dry bread will remain un- 

 changed and a fuzzy growth will soon appear on the moist 

 bread. This fuzzy growth later turns black. This growth 

 is composed of a large number of little mold plants (see 

 figure) which take root on the surface of the bread, obtain 

 their food from it, grow in time so as to cover it, and produce 



