I often wonder why yeast starters for various lager yeasts are done at room temperatures. Wouldn't that just encourage the evolution of those yeast cells which prefer higher fermentation temperatures? Are there any studies done which indicate that it would be preferable to do a yeast starter for lager yeasts at a much lower temperature, approaching the normal fermentation temperatures for lager yeasts (i.e. about 50 F)?
It's faster. And often easier. Metabolically speaking, lager strains do prefer higher fermentation temperatures than the ones at which we usually ferment . It's brewers that prefer to ferment lagers at lower temps, because it limits ester production. That said, if a colony were re-pitched and fermented warm over many generations, it's possible that the strain could evolve (through genetic drift) to be less efficient at lower temps than the original strain was. I have heard a few brewers make this claim, without evidence. I haven't seen any studies.
Thank you, @VikeMan. Yeast manufacturers do suggest to do yeast starters at room temperature, and I suppose that would be fine if you were reusing the yeast once or twice. I do wonder what effect it would have with repeated use.
