Originally Posted by klnosaj
Generally, use the highest temperature the beer reached during or after peak fermentation. That's often the temperature the beer is currently sitting at, but not always. As an example, if I make a lager, I ferment it at 50 degrees. Then I raise the temperature to 65 degrees after fermentation for a diaceytl rest. Then the beer is racked and lagered at 34 degrees, and then bottled at 34 degrees. The temperature that should be used is 65 in that case. The reason is that more co2 is not produced after fermentation, so the cold temperature after fermentation ends isn't going to create more co2.
Another example is that I made an ale that fermented and sat at 65 degrees. I cold crashed it to clear it up for 3 days at 33 degrees. Then I'd use 65 degrees.
Alternatively, say you fermented a beer at 55 degrees but then let it sit at room temperature for the last few days. Any excess residual co2 would have bubbled out, and not been retained the way it would at 55 degrees, so I would use the room temperature.
I hope that makes sense!
It's not really on topic, but I hate priming calculators! They have you carb "to style" but some beers are going to be flat (English brown ale at 1.5 volumes) and I think that's unexpected for most people who expect carbonation in bottled beer. It's different when having a true English cask ale, of course, but their "style" guidelines stick that way. Or worse, they suggest carbing to 4.48 volumes for a weizen. Yes, a weizen is typically well carbed, but 4.48 volumes in a bottle can be a foamy mess, if not explosive. Just always consider the "style guidelines" as something you might get in a pub and not out of a commercially bottled beer and consider that many beers that come out of a bottle are 2.2-2.7 volumes or so, regardless of style. If something seems too low or too high to seem correct, it probably is worth double checking to ensure good results.