I took a family/kid induced hiatus from brewing and just recently got back in. I made a simple Smash IPA and has been in primary for a little over two weeks. It was finished fermenting at the 8 day mark. It's been at 66 the entire time, my question is should I warm it up a couple of degrees, to maybe around 70, for a few days? Or let it ride out at 66 and start my cold crash on Friday? Yeast is 1056.
If you have fermentation by-products such as perceptible diacetyl in your beer than raising the temperature may expedite the 'cleaning up' process. Or the beer can clean up at 66 degrees. Your choice here. Cheers!
Ideally, if you would want to ramp the temp a little...do it while it still has a couple gravity points to go.
I doubt that raising the temp at this point would do much. If the yeast are done, they're done. They won't reactivate to do anything with warmth and no food. Like @GreenKrusty101 said, you would normally do this a few days into primary fermentation as it starts to slow down. I also doubt that 2 weeks at 66 on 1056 will have any off flavors that need cleaning up.
How does the beer taste? I usually taste after 1 week to evaluate where the beer is, but typically I do not move the beer out of primary for at least two weeks just in case there is some cleanup that the yeast can do. I agree with jbakajust1 that if the yeast are truly done, simply raising the temp a few degrees will not pull them out of dormancy. However, there is some yeast activity that may be occurring a few days after gravity stabilizes, such as acetaldehyde or diacetyl cleanup. These are not typical problems for most fermentations with this yeast. Of the two, I have once experienced acetaldehyde with US-05, a dry yeast strain similar to 1056, when I rushed a beer. At the time, I was a bottler, so my routine involved reactivating yeast in the bottle with priming sugar addition, and this seemed to take care of my issue.
The sample tastes and smells great. I had planned on raising the temp towards the end of fermentation, but it happened a lot quicker than I expected and I didn't have the opportunity to do it. I'll be more prepared next time to raise it up earlier. Thanks for the feedback all.
Diacetyl can still be formed after attenuation is finished. And when that's the case, raising the temperature accelerates both the formation and the cleanup. That's not to say that your beer is going to have noticeable diacetyl. It probably won't. I just wanted to point out there may be cases where a rest at a higher temp is useful, even after attenuation is done.
Neat thing, diacetyl formation and reduction. It's excreted from the cell as a precursor (acetolactate), biotransforms into diacetyl in intercellular space, then is resorbed into the cell and transformed into acetoin then, eventually, into butanediol. The neat part, for me, at least, is that acetolactate can be transformed into diacetyl non-enzymatically, via redox reactions. Nice discussion of it here if anyone is interested.
