How long is too long to let a beer sit on a yeast cake and reuse the same yeast? I have a flanders red that has been sitting for 1.5 months and I'd like to use the yeast for another beer soon.
It depends on many factors, I think the most important are temperature and ABV. If you have let it rest for a 1.5 month at a relative low temperature( say less than 68 F) I think your yeast will be fine to be reused, maybe it is not the best way to preserve a yeast but I think it won´t be too deteriorated.
I'd taste for oxidation at this point. Maybe not noticeable in a beer that's only a few months old, (due to the beer being green), but this would be my first concern. I'd lean towards a good yeast washing and a starter if you proceed.
I've been thinking about doing this. With yeast being pretty costly, I wonder what the process is for harvesting and reusing. I'm gonna check put he good old YouTube.
