The Story of Yeast
Yeast in History
Man used yeast before he knew how to write. Hieroglyphics suggest that the
ancient Egyptian civilizations were using living yeast and the process of
fermentation to cause their bread to rise over 5,000 years ago. Of course, they
didn’t know what was responsible for the leavening process, and probably looked
upon the chemical action of yeast as a mysterious and unreal phenomenon.
Leaven, mentioned in the Bible, was a soft, dough-type medium kept from one
bread baking session to another. A small portion of this dough was used to start
or leaven each new lot of bread dough.
It is believed that since early times, leavening mixtures for bread making were
formed by natural contaminants in flour such as wild yeast and lactobacilli,
organisms also present in milk.
Yeast Today
Centuries later, scientific research revealed that yeast is actually a tiny
microorganism, visible only with a microscope. The chemical action and growth
of yeast that causes dough to rise then became apparent.