1050 Rural School Leaflet 



growth of yeast is 70 to 90 F. It may be lower than this, and in that 

 case the yeast grows slowly; or it may be somewhat higher, but this con- 

 dition may weaken the yeast and thus make it a prey to its enemies. 



The enemies of the yeast-plant are just as small and invisible as the 

 yeast-plant itself, but we must not take it for granted that they are not 

 present because we cannot see them. They may be found on soiled 

 towels and hands or on unclean utensils; in milk and water and poor 

 flour ; and if they get into our yeast garden they may choke out the yeast 

 and grow in its place. Then, if we are using the yeast to make bread, 

 instead of having sweet, well-risen bread we shall find a sour, poor loaf that 

 is neither good nor wholesome. If the yeast is to grow vigorously and 

 produce new plants, it must have not only food but also considerable 

 moisture. It may be kept alive for a long time in a dry state, but in 

 that condition it will be quiet and inactive. The dry yeast-cake and the 

 compressed yeast-cake so familiar to housekeepers are fields of dried-out 

 yeast-plants, alive but inactive and requiring only moisture, warmth, 

 and food in order to start fresh growth. 



In former times bread was made light by setting some dough in a warm 

 place until it began to ferment. That was before anything was known 

 about yeast, and no one dreamed then that the fermentation was due to 

 certain little wild yeasts that had found their way from the air into the 

 dough. That was not the surest way of making good bread, for while 

 the wild yeast was getting in there was nothing to keep the other little 

 living things out and the bread was often sour and unwholesome. Care- 

 fully weeded fields of cultivated yeast-plants are now within the reach 

 of every one in the form of either dry or compressed yeast-cakes, and 

 it is no longer necessary to depend on wild plants to do the work. The 

 housewife often makes what she calls a " starter " and uses this in place 

 of the yeast-cake in making her bread. The starter is made by planting 

 yeast in a field that contains just enough food to make it begin active, 

 vigorous growth. If starter is used the bread rises much more quickly 

 than when dry yeast is used, because the yeast-plants are more numerous 

 and more active in the liquid starter than in the dry yeast-cake. Some- 

 times a little of the sponge is saved from one baking to another, 

 and this sponge is used for making the bread light. It is just like saving 

 seed from one crop in order to start a new crop. Bread made from left-over 

 sponge is less likely to be good than when specially prepared yeast is 

 used. 



There is no process in household management that is more interesting 

 than bread-making, for it deals with living, growing things. Proper care 

 and an understanding of conditions will, as a rule, insure good results; 

 and when bread fails to be good there is always the consolation of knowing 

 something of the cause of failure — either poor, weak yeast-plants, or 



