| The tantalizing aroma of bread baking in the bakery
is due to a process called fermentation of baker's yeast, or Saccharomyces
cerevisiae. These organisms have long been utilized to ferment the
sugars of rice, wheat, barley, and corn to produce alcoholic beverages
and in the baking industry to expand, or raise, dough. |
Dry yeast available in the grocery store is a collection of dormant yeast
spores. Once these spores are mixed into water and dough, the culture is
active. To start this germination process and make the bread rise faster,
the baker sometimes mixes yeast with water or milk before adding to the
dough. |
 The
yeast's function in baking is to ferment sugars present in the flour or
added to the dough. This fermentation gives off carbon dioxide and ethanol.
The carbon dioxide is trapped within tiny bubbles and results in the dough
expanding, or rising. Their usefulness is based on their ability to convert
sugars and other carbon sources into ethanol in the absence of air (anaerobic),
and into carbon dioxide and water in the presence of air (aerobic). |
