When brewing our stronger beers, my brew buddy and I make a small batch of a weaker beer with our not quite spent grains. Our last batch was a 12 gallon imperial stout, where we made a 1.5 gallon batch of a weaker stout on the stove top.
The imperial stout ages for six weeks, while the weaker stout is ready to bottle after two (yes, I proudly bottle). So last week I bottled the weak stout and today it was ready to taste. Holy crap there was a big buttered popcorn aroma! Way too much diacetyl. I'm very confident in my sanitation. So I'm ruling that out. What I think happened, is we had two very warm days to start off the fermentation cycle. Then it got really cold.
Used WLP001 Cali Yeast that started at 68F for those two days. Then it cooled all the way down to 55F (by the time I checked a week later).
Both the stronger beer and weaker beer were on the same cycle.
The stronger beer is still in the carboys. And my question for the forum is, is there anything I can do to get the yeast to reassimilate the diacetyl from the imperial stout at this point? I moved the carboys to the upstairs where they'll get back up to 68-70F. After 3 weeks, will warming it up get the yeast rolling again?
Any other suggestions? Thanks.