What Is Yeast ?

Yeast is a fungus used to make bread rise and to ferment alcoholic beverages.  There are many different species of yeast, and each has its own special function.  The yeast that makes bread rise is a different yeast than the one used to make beer.  The bread type eats the sugars in the flour and other ingredients in the dough, digests them, and excretes carbon dioxide.  This is what makes the dough airy.  The beer type eats the sugars in the grain used to make the beer, digests them, and excretes carbon dioxide and alcohol.  Yes, though it sounds gross, alcohol is the natural waste product of a fungus.  Makes you wanna rush out and have a beer, right?   ;-)

Yeast also has a place in the bio-tech industry.  I used to work for a company that made a medicine for Rheumatoid Arthritis.  The medicine was a living organism.  That organism's main food was a particular species of yeast.  The medicine organism ate the yeast, and this was its energy source for reproduction.

I hope this helped.