Standard Rule?

[BBKing]

I've seen the whole "the temp inside your fermenter is 10 degrees warmer than the outside" discussion here a few times, and I was wondering if thats pretty standard or not.

Due to cold temps and a closet thats right off of the exteriour wall of the house, I have a batch of Nut Brown Ale thats fermenting at like 57 degrees.

If its a pretty set rule, I'm not gonna worry too much about it, but if not I think its time for a warm bath

 

[albannach]

For large (15+ gallon) batches during high krausen, I would say it could be 10 degrees F warmer. My 5 gallon batches at high krausen are only 3-4 degrees F warmer than ambient, and once fermentation slows down, they match ambient temperature.

I use a warm water bath (with an aquarium heater) to maintain my desired fermentation temperatures during cold months.

 

[BBKing]

Right on, thanks

 

[Hermit]

I got 8 degrees in a five gallon carboy by insulating it with several towels.