What are yeasts?

Yeasts are single-celled fungi.  

How many species of yeast are there?

Over 2000 species of yeast have been described.  The most familiar yeast species is Saccharomyces cerevisiae, which has been used by humans for thousands of years to make bread, beer and wine.  This yeast has been described as the “first domesticated organism”.  Other yeast species include Candida albicans, a pathogenic species that causes yeast infections.  There is a lot that we don’t know about yeast species, though.  It is estimated that less than 1% of yeast species have been discovered!  You can learn more about the taxonomy of yeasts and other fungal species at mycobank.org. [link]

What are yeasts used for?

The species Saccharomcyes cerevisiae is not only used for production of beer, bread, and wine.  This species also plays an essential role in the production of a broad diversity of industrial chemicals, food ingredients, and pharmaceuticals.   This species is also a popular model system for biological research.  Wonderful discoveries have been made regarding the function of cells using S. cerevisiae and also the fission yeast species Schizosaccharomyces pombe, such as the 2001 Nobel Prize research of Hartwell, Nurse and Hunt.

Specific information on the uses of yeast in baking, home brewing, and home wine-making is available from commercial yeast suppliers.  Very useful information is available from the following web sites:

Lallemand: home winemaking and home brewing
http://consumer.lallemand.com/

Wyeast: yeast for wine and beer
http://www.wyeastlab.com/

Red Star Yeast: wine, nutritional, and baking yeast
http://www.redstaryeast.com/

Fleischmann’s Yeast: baking yeast
http://www.breadworld.com/