Baker's 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 leavened baked goods (breads, Danish pastries, brioche, 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).

Fresh yeast is ivory colored with a yellowish hue and is soft and moist and should easily crumble. Make sure it fresh smells and there are no dark or dried places on the yeast. It is mainly used by professionals as it is highly perishable and must be used within a short time of opening. It is must be refrigerated. For longer term storage it can be frozen. Compressed yeast contains about 70% moisture. It needs to be proofed before using and should have a pleasant yeasty smell and be foamy.