Explore the Science of Yeast | 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.