Does temp matter after reaching FG?

[Deskjockey894]

So say the beer has been in the primary for 2 weeks and has reached its FG. At this point, assuming the temperature doesn't go above 70 F (not a remote issue where I live in March) does a drop in temperature really matter? I plan to keep the beer in the primary for 4 weeks (2 weeks remaining), so if the temperature say fell to the low 60s, high 50s is this even an issue? The way I was thinking, the yeast have already done their job with the fermentation process. Does temperature matter in terms of "cleaning up" for the 2 weeks left that I plan to leave in the primary?

 

[MalFet]

There are many metabolic processes that don't neatly correspond to FG change. Your yeast will produce intermediate compounds in the course of fermentation (acetaldehyde and diacetyl are the big names, but there are many others) that they will break down even after FG has been reached. That said, aging cool can also be a good thing. So, unfortunately, the answer to your question is, "It depends". Taste should be your ultimate guide. Cool will help solids drop out of solution; warm will help the yeast break down intermediate metabolites.

 

[pericles]

I agree with MalFet, but I also think that, after two weeks, your beer is probably done with most of the fermenting and conditioning that temperature affects. While swings in temperature are never good for your beer, they won't cause radical changes at this point.

 

[donjr721]

i would transfer to a secondary just so your brew isn't sitting on the old yeast, 4 weeks shouldn't be a problem though, just don't know if the temp will affect autolysis of the yeast or not. i have read that some people leave brew in primary fermenter for 4 weeks without any problems. i'm just not sure about the temp though.

 

[MalFet]

i would transfer to a secondary just so your brew isn't sitting on the old yeast, 4 weeks shouldn't be a problem though, just don't know if the temp will affect autolysis of the yeast or not. i have read that some people leave brew in primary fermenter for 4 weeks without any problems. i'm just not sure about the temp though.

I've left beer on yeast for months without detectable levels of autolysis. Even John Palmer, who is responsible for much of the talk about autolysis based on the first edition of his book, now says it is largely a non-issue.

 

[unionrdr]

My latest brew will be on the yeast cake 4 weeks by the time I'm done dry hopping & bottle this Sunday. I dropped the hop bag in last Saturday,& it smelled clean & wonderful. No worries,m8.

 

[Deskjockey894]

Thanks for the input (amazing how the post metamorphosized into the great to secondary or not debate?). The real basis for my question is because I use a beer belt heater to ensure my temperatures can stay around the 68 - 72 F mark (ideal for the yeast im using), but after full fermnetation is complete and their is no risk that the yeast will fall asleep from cooler temperatures (once i remove the belt), I would like to start a new brew and use the beer belt for my other primary fermentor. So basically I just wanted to ensure that I didn't need to rigorously monitor the temperature and that there would be no detrimental effects if the temperature did fall after the beer reached FG.