Talk:Saccharomyces
DanABA (talk) 20:10, 23 December 2022 (MST) Regarding study heat resistance in diastatic strains: https://www.sciencedirect.com/science/article/pii/S0362028X22000321 - Bryan Heit says:
"While interesting, I don't think this would affect breweries much: 1) While brewers yeast can sporulate, it rarely does so on its own. This paper used special medium to force sporulation, so without showing sporulation under brewery-relevant conditions, it's not clear whether this is at all relevant outside of the lab. 2) this doesn't tell us much about diastaticus; it's the only strain they tested, and it's hard to imagine a non-diastaticus strain wouldn't do the same if put under the same conditions. 3) even if sporulation happens in a brewery, I have trouble seeing how this specific situation would arise. It would require sporulation conditions to form, followed by pasturization, followed by the yeast getting back into a growth permissive environment...only to sporulate again and somehow move through the same process. Unless a brewery is dumping pasturized beer back into fresh wort (or running finished beer through their wort chiller), I don't see how such a cyclical process could occur."
MTF link: https://www.facebook.com/groups/MilkTheFunk/posts/6460688047292688/
Richard Preiss responds to Bryan:
"Yep that covers it. I do know that yeast spores are quite heat resistant, much more so than most brewing bacteria. This is why most pasteurization recommendations center on log reduction of yeast spores for determining efficacy. But I agree with Bryan that a situation where yeasts are able to repeatedly sporulate in the brewery might be rare. Two areas that could come up and where we have traced some brewery diastaticus contaminations is the heat exchanger and hoses. If these are getting repeatedly heated and cooled but have some biofilm formation or other ways for "pockets" of microbial communities to thrive, then it's possible that resistance accumulates over time like the paper describes. And while there *shouldn't* be viable diastaticus in a brewery heat ex or hoses, I can say based on experience that it happens. Especially when hoses are treated as assets rather than consumables, and when heat exchangers don't get preventative maintenance."