2 weeks ago I brewed an oatmeal stout. I was at FG after one full week of fermentation in my freezer. I took it out of the freezer last saturday and allowed it to come to ambient temps (around mid to high 70’s). It was at that for a full week. The question is, how long does the “yeast clean up” period take? How do we know when it’s done? Should I just let it sit for another week. I plan to brew tomorrow and so I can use the freezer for this new ferment and allow the stout to sit for another week. But if I could be confident that the job is complete I may keg the stout tomorrow after brewing.
Time to “clean up” depends on a bunch of factors, like the yeast strain, the fermentation temperature, and the OG of the beer. My rule of thumb is 3 weeks after brew date and an ale will be ready to keg, unless it is high OG (that adds another week or so). That assumes good temperature control like you obviously had. With good temperature control during the active stage of fermentation, the time-limiting factor is flocculation rate. If you were using a British yeast, you could likely cut that a bit finer and it may be good now, as Brit yeasts tend to settle out very fast.
I used Nottingham. My OG was 1.080. I love Nottingham because it flocculates like crazy. It makes for a very nice clear, clean beer. The FG was 1.016. I think I will just let it sit another week. Why rush?
There should be no cleanup required for most ale yeasts including Notty. My rule of thumb: After you’re positive that fermentation is complete, wait another 3-4 days just to make sure, then bottle or keg. No conditioning time required for most ales. It wouldn’t hurt to wait a whole week… but why?
OK Dave. That’s good to know. So after fermentation is complete, does the 3 or 4 additional days allow enough time for all the particulate matter to drop out? Or is that better accomplished by cold crashing? I like to get as clean a beer as possible into the keg. I had a batch once where the last few pints dragged a fair amount of crap from the bottom of the keg. was never sure why that happened but I did not use Nottingham for that beer. I never seem to have issues like that with Nottingham.
Particulates drop out with time, and they drop out faster if the beer is cold. Cold crashing is just a way of speeding the process that happens naturally. If the beer is otherwise clean tasting, there is no penalty to cold crashing. But in my experience, all beers need some time to get clean tasting, and simply cold crashing as soon as active fermentation is done is not a great idea for that reason.
I condition the extra 3-4 days to make absolutely certain that the fermentation has ended, to avoid gushers since I bottle. If you keg it probably doesn’t even matter that much. But then of course there are the benefits of additional clearing that happens with more time, also any sulfur or diacetyl that might be present will be reduced by the yeast. I like to condition warm so the yeast can consume these things. If you cold crash, then you might get a beer that clears faster, but might also lock in these off-flavors that the yeast has the ability to consume. So, for each batch, consider which is more important, then choose your conditioning temperature based on that. Seems to make the most sense.
In my experience stouts and porters do well with a little time. If it were mine, I’d keg it and let it sit at room temp for awhile then chill and carb. If your worried about " gunk" push it to another keg after its carbed up.