Yeast Essential for Bread Making

The most fascinating sight in a bakery is seeing small mounds of dough rise to voluminous, well shaped breads and the baker does this by adding 'Yeast' to the dough.

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This one-celled microorganism called Yeast grows all around us. In the presence of food and water it grows, but in their absence it suspends growth when it becomes light enough to be blown by the wind. Present on human skin, it can be transferred to food through contact. Referred to as 'the oldest plant cultivated by man', it has found application since thousands of years.

Yeast acts as a catalyst in the fermentation of bread. As an effective leavener, Yeast feeds on sugar in the flour and produces carbon dioxide which makes bread rise. This carbon dioxide fills thousands of balloon like bubbles in the flour and with no place to go, the flour rises. On baking, this is what gives the bread its airy texture.

The most common strain of Yeast used for baking purposes is called saccharomyces cerevisiae. Bakers and baking companies have developed several strains of yeast for gas production and fermentation.

The Yeast Types

Special strains of yeast have also been created for lean doughs or enriched doughs. Just like brewers have different yeasts to choose from, bakers too have access to many types of yeast strains. However, the public has only a few strains from which to choose.

The first, Active Dry Yeast, has a larger particle size than Instant Active Dry Yeast, making it necessary to proof, usually with water, before using and the recommended water temperatures vary between 100-115 degrees F.

Active Dry Yeast will last well beyond its expiration date for one year if unopened at room temperature and will survive longer if frozen when it can be used directly without thawing. If opened, Active Dry Yeast will survive for six months in the refrigerator and 12 months in the freezer.