Yeast is a simple plant, which can be dehydrated or compressed together in cakes and stored in the refrigerator.
Dehydration and storage will not kill the yeast cells as long as the yeast is kept at a cool temperature.
Cake yeast, which has some moisture in it, can be kept for only a few weeks in the refrigerator.
When warm water is added to the yeast, along with food in the form of sugar, the yeast cells will grow and multiply giving off carbon dioxide, which will cause the dough to increase in volume.
The process is called â€œfermentation.â€
During baking, the carbon dioxide production and formation of ethyl alcohol will cause the gluten of the dough to stretch and bread will then increase in volume, while the gasses dissipate.
The only ingredients needed to make satisfactory yeast bread are: FLOUR, YEAST, and warm WATER.
Every other ingredient is extra and each will affect the volume, texture, color, and flavor of the yeast bread.
Breads, like a plain white or wheat sliced bread, are usually non-sweet with few extra ingredients beyond some eggs, milk and shortening.
Dinner rolls or sweet yeast breads have a richer dough with some sugar and more eggs, shortening, milk, and other ingredients.