Potential dumb question... Is it ok to allow the fermenter to drop out of the temp range for the yeast after most of the activity is finished? I always try to keep it in the range of the particular yeast but recently got to thinking how necessary that is. Does fermentation temp refer to the active phase or the entire time in primary?
I like to maintain the temp in the fermenter at the same level at which it 'peaked,' up until it's time to package/crash/lager/whatever. It may not be necessary, but I look at it as some insurance that the yeast activity won't drop off before 'cleanup' is done.
After the gravity has stopped dropping I generally let it sit at room temp. If I had a nice temperature controlled fermentation chamber I am sure it would be different and I would keep it at the desired temp but I have yet to notice any ill effects.
It is perfectly acceptable to either warm a beer up or chill it after primary is over. Either or both could actually be recommended depending on the beer style. Ever heard of a lager?
Good point. Perhaps i should have been more specific, i currently have a Saison going and i know they are supposed to be kept warmer but the noticable activity has been done for awhile now.
If it's done then I say you're fine. If you're bottling make sure it is definitely finished fermenting. One potential issue I can see is if the saison yeast are not quite finished and you chill it, then you may end up with residual CO2 + too much bottle fermentation = overcarbonation. Cold beer hangs on to more CO2.
You just want to make sure you hit your final gravity. Especially when you cool yeast, you risk the chance of not finishing fermentation by shocking them. Allowing the yeast to warm is ok.
