Subscriber Beer Trader. Depends on what your primary fermenter.. Buckets being the worse, better bottles, and then glass carboys. Then maybe if you are serious about it, a SS conical, but not a ton of people use them. As a whole, I try not to leave them in longer than 2 weeks after fermentation is done. Life gets in the way, and I haven't had them get worse, obviously keeping them fresh for a hoppy beer is best. #2 Apr 14, 2014.