If the yeast plant has to go for a long time without food and water, it will sometimes divide into spores (a kind of seed). The outside wall will then break down and these spores will float around in the air until they are given the right conditions when they will commence to grow the same as the original yeast cell. These spores can stand more unfavorable conditions with- out being harmed than the yeast cell. BREAD MAKING 225 Method by Which Yeast Raises Dough. As the yeast plant grows it changes the sugar into alcohol and into a gas called carbon dioxide gas. When these bubbles of gas are given off inside the bread dough, they are caught and held by the rubber-like gluten in the flour and in their efforts to escape push the dough up and cause the bread to rise and become light and porous. This process of changing sugar into alcohol and carbon dioxide gas is called fermentation. Effect of Heat on the Yeast Plant. If any plant is to grow well it must receive the right amount of heat as well as the proper soil. Bearing in mind the fact that the faster the yeast plant grows the more bubbles of gas it will give off, the results of the following experiments will show at what temperature the yeast plant thrives best. Experiments. Put 1 t. molasses into each of three glasses. Soften a cake of compressed yeast with 2 T. of water. Put one-third of the softened yeast into each glass. Ex. 1. Pour one-half cup of cold water into one glass of yeast and molasses and set it into the ice box or out of the window if the weather is cold. Ex. 2. Pour one-half cup of luke warm water into another of the glasses of yeast and molasses and set the glass into a pan of warm water. Ex. 3. Pour the yeast and molasses in the last glass into one-half cup of boiling water and when cool enough so it will not break the glass pour it back into the glass and set it into a pan of luke warm water. In half an hour examine the three tumblers. In which is ihe yeast working best? 226 FOOD AND COOKERY Place the glass from the ice box into a pan of warm water. Does any change take place? What effect does cold have on yeast? What is the best temperature for your bread if you want it to rise? Yeast grows bt-st at a temperatture of 70° to 80° Fahren- heit. At 160° F. or over, the yeast plant will die. At a very low temperature, the yeast plant is chilled and its action is made slower, but if the temperature is then raised to 70°, the yeast plant will revive and commence to work. Kinds of Yeast. Compresse(J yeast, dry yeast, liquid yeast and wild yeast are all used in raising bread. Compressed yeast is obtained from the distilleries. It is washed many times to remove the impurities, is then mixed with a small amount of starch and pressed into cakes. These are wrapped in tinfoil to exclude the air and kept in a cool place until used. There are many millions of yeast plants in each two-cent cake of yeast. Dry yeast is made by mixing the distillers yeast with corn- meal. It is then pressed into cakes and dried. Dry yeast will keep much longer than compressed yeast, but is a little slower to act when making bread. Liquid yeast is made by mixing a cake of yeast with boiled potatoes, salt and the water in which hops have been steeped. This is allowed to stand until the yeast grows and fills the whole mixture with bubbles of gas. A cupful of this yeast is used to lighten the bread dough; The last cupful of each mixture of liquid yeast can be used to start a new mixture of potatoes, hops and water. So many bacteria get into this yeast from BREAD MAKING 227 the air that after a time it will be necessary to start the liquid yeast afresh with a cake of compressed or dried yeast. The bacteria would give the bread a bitter taste.

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If the yeast plant has to go for a long time without food and water, it will sometimes divide into spores (a kind of seed). The outside wall will then break down and these spores will float around in the air until they are given the right conditions when they will commence to grow the same as the original yeast cell. These spores can stand more unfavorable conditions without being harmed than the yeast cell. Method by Which Yeast Raises Dough. As the yeast plant grows it changes the sugar into alcohol and into a gas called carbon dioxide gas. When these bubbles of gas are given off inside the bread dough, they are caught and held by the rubber-like gluten in the flour and in their efforts to escape push the dough up and cause the bread to rise and become light and porous. This process of changing sugar into alcohol and carbon dioxide gas is called fermentation. Effect of Heat on the Yeast Plant. If any plant is to grow well it must receive the right amount of heat as well as the proper soil. Bearing in mind the fact that the faster the yeast plant grows the more bubbles of gas it will give off, the results of the following experiments will show at what temperature the yeast plant thrives best. Experiments. Put 1 t. molasses into each of three glasses. Soften a cake of compressed yeast with 2 T. of water. Put one-third of the softened yeast into each glass. Ex. 1. Pour one-half cup of cold water into one glass of yeast and molasses and set it into the ice box or out of the window if the weather is cold. Ex. 2. Pour one-half cup of luke warm water into another of the glasses of yeast and molasses and set the glass into a pan of warm water. Ex. 3. Pour the yeast and molasses in the last glass into one-half cup of boiling water and when cool enough so it will not break the glass pour it back into the glass and set it into a pan of luke warm water. In half an hour examine the three tumblers. In which is ihe yeast working best? Place the glass from the ice box into a pan of warm water. Does any change take place? What effect does cold have on yeast? What is the best temperature for your bread if you want it to rise? Yeast grows best at a temperature of 70° to 80° Fahrenheit. At 160° F. or over, the yeast plant will die. At a very low temperature, the yeast plant is chilled and its action is made slower, but if the temperature is then raised to 70°, the yeast plant will revive and commence to work. Kinds of Yeast. Compresse(J yeast, dry yeast, liquid yeast and wild yeast are all used in raising bread. Compressed yeast is obtained from the distilleries. It is washed many times to remove the impurities, is then mixed with a small amount of starch and pressed into cakes. These are wrapped in tinfoil to exclude the air and kept in a cool place until used. There are many millions of yeast plants in each two-cent cake of yeast. Dry yeast is made by mixing the distillers yeast with cornmeal. It is then pressed into cakes and dried. Dry yeast will keep much longer than compressed yeast, but is a little slower to act when making bread. Liquid yeast is made by mixing a cake of yeast with boiled potatoes, salt and the water in which hops have been steeped. This is allowed to stand until the yeast grows and fills the whole mixture with bubbles of gas. A cupful of this yeast is used to lighten the bread dough; The last cupful of each mixture of liquid yeast can be used to start a new mixture of potatoes, hops and water. So many bacteria get into this yeast from the air that after a time it will be necessary to start the liquid yeast afresh with a cake of compressed or dried yeast. The bacteria would give the bread a bitter taste.

Student's manual in household arts