Part 15: Yeast and Flavor in Beer

White Labs California Ale Yeast. Image via Beer-Wine.com

This blog will soon post an audio diary on making beer with liquid yeast instead of dry yeast.

The liquid yeast used was White Labs' California Ale Yeast.

In doing research, a helpful article by Christohper White entitled "7 Fascinating Facts About Yeast" proved to be quite interesting.

Of the 7 interesting facts, perhaps the most interesting is that yeast provides most of the flavors and aromas in beer.

To an untrained brewer, taste could be thought of as coming from the variety of grains or hops that the brewer decided to boil with his beer. White says this isn't true.

All of the flavors already in the wort are changed by the yeast, adding 600 flavor and aroma compounds to the finished product.

"For example yeast change the way malt and hop compounds taste and smell," he writes. "Hops are affected because different yeast strains adsorb different amounts of iso-alpha-acids, which account for 60 percent of beer’s bitterness. Malt components are affected because they are metabolized by yeast."

Yeast does much more than produce the alcohol that makes beer worth drinking.