I read on rec.crafts.brewing that "diammonia phosphate and urea" is a yeast nutrient, and the post also mentioned a "yeast energizer", speculating that it might just be vitamins. What is the difference between a yeast "nutrient" and an "energizer"?

Thanks.
Bill Velek

RESPONSE:

I have read repeatedly that yeast will mutate after several reuses in the homebrew environment. If the yeast mutate at this high of a rate, how do breweries maintain consistent yeast characteristics, and how are pure cultures maintained without mutations?

I've read somewhere (but cannot find it anymore) that yeast will multiply until they reach a certain density (cells/ml) or exhaust their supply of sterols, whichever comes first.

First, thank you so much for giving us some of your time. My question concerns yeast growth as it relates to flavors in beer. I have read several articles mentioning that yeast growth is important to flavor production in beer, and that the amount of yeast growth is related to the amount of yeast pitched.

Like everyone else, I really do appreciate your help and understanding and I hope my questions won't be too silly for you.

We're told yeast will adapt to the medium, at least for scale. But does it also adapt to other characteristics of the medium? If so, would it be possible to lead a yeast strain to adopt different characteristics for further batches?