[quote=“maltybeer”][quote=“rebuiltcellars”]The companies that sell yeast grow it that way, and there is no actual limit to how long you can keep a strain of yeast going. The risk though is that the yeast will evolve over time into a strain that doesn’t have the same characteristics as it started with. The companies have stringent quality control checks to make sure that the cells they feed to propagate match what they want. Most homebrewers don’t have the knowledge or equipment to do that.
I will rarely use a package of yeast for just one batch, and have gone to 7 or 8 generations on occasion. But I take a break from brewing in the summer and I’ve found it doesn’t really make sense to try and revive a strain after a long storage.[/quote]
Have you noticed a difference in taste from using a 7th or 8th generation yeast strain?[/quote]
No, never noticed a taste difference. I did notice differences in the fermentation dynamics. In general, they tended to improve over the first few generations and then stay there.
I also noticed some situation specific changes. If I oxygenated properly, I would notice that the next time I pitched the yeast (beer after the one with good oxygenation) the yeast would take off much more strongly than if I was lazy about adding oxygen on the brew before, and the effect seemed to increase with more generations. I also noticed a change in flocculation during the time I was experimenting with washing my yeast, with the yeast getting harder to clear over a couple of generations. I guess however I was doing it, I was selecting for less flocculent cells.