LVBen
Well-Known Member
If the bottle is old beware that the yeast remaining may be pretty stressed and you may be selecting for yeast with mutations that are not going to be beneficial for brewing. My first rescued yeast was from a Stone IPA that had sat around quite a while in the warm and I seem to have grown up something that produced a lot of off flavors. I also just heard second hand that Stone uses a different bottling yeast. Not sure if that is the case but it is worth considering the possibility.
I think it is a good idea to taste the beer before using the yeast. If the beer tastes off, then don't use the yeast, but if the beer tastes good and fresh, then the yeast is probably equally good and fresh.