Active Dried Yeast

The word "yeast" comes from the Sanskrit 'yas' meaning "to seethe or boil". Yeast is a living organism and is in the air around us. It is a member of the fungus family and is a single-celled fungi of which there are about 160 different species. Baker's Yeast as well as Brewer's Yeast belong to the Saccharomyces Cerevisiae species. Louis Pasteur in the 1850's is credited with first discovering and understanding the fermentation process which led to the development and cultivation of the yeast we use today.

Baker's yeast, like baking powder and baking soda, is used to leaven baked goods (breads, Danish pastries, brioche, and croissants). The difference between these two leaveners is that baking powder / soda react chemically to produce the carbon dioxide that makes the baked goods rise. Yeast, on the other hand, is a living organism and the carbon dioxide it produces is the result of the yeast feeding on the dough.

The two forms of Baker's Yeast are; compressed cakes (also called fresh yeast) and dehydrated granules (dry yeast).

Dry yeast is fresh compressed yeast that has been pressed and dried until the moisture content is only about 8% which makes the yeast dormant. The granules only become active again when mixed with a warm liquid. The advantage of dry yeast is it has a much longer shelf life than fresh yeast and does not need to be refrigerated. This makes it a favorite among home bakers. The tiny, dehydrated, bead-shaped, sand colored granules but once opened, the yeast needs to be stored in the refrigerator away from moisture, heat, and light because once yeast is exposed to air it deteriorates rapidly.

There are two types of dry yeast: regular active dry and rapid-rise. The two types of dry yeast can be used interchangeably. The advantage of the rapid-rise is the rising time is half that of the active dry and it only needs one rising. However, you do sacrifice flavor and texture in order to save time as the yeast does not have time to develop its own flavor.