BlackHat
Well-Known Member
I'm planning on some half batches (2.5 gallons), but I don't have equipment geared for half batches. I know that in secondary fermentation you want to have the least amount of head room in your carboy as possible, but what about primary fermentation - can I get away with 2.5 gallons in my 5 gallon carboy? Is there a maximum amount of head room for primary and secondary fermentations?