Any issues with this, regarding head space or anything? also, if you are making a 2 gallon batch, then would a 3 gallon fermenter be ideal, so there is a little room for krausen, or whatever, if one didnt want to use a blow off tube, say for a Hefe? thanks
The general rule is about 15% larger fermenter than your brew. More than that allows for too much headspace, which increases the risk for oxidation and infection. 3g in a 6g fermenter is not a good idea. As for the 3 gallon fermenter, I'd consider at least a 2.5g brew.
I’m going to come in on the opposite side of this and say it’s not a problem at all. The extra space gets filled with CO2 once the yeast get going anyway (and before they get going, they need oxygen.). Smaller fermenters are cheaper, easier to handle, and take less space, but I’ve done a fair number of 2.5-gallon batches in a 7-gallon fermenter.
^^^^This, I routinely brew
6g batches and split into two 5 or’6 gallon better bottles for primary and if I’m doing a secondary I then use 3 gallon better bottles. I’ve never had an issue with oxidation, etc in 12+ years.
I make 2.5 gallon batches. currently I use a 3 gallon fermonster. before that a 3 gal Brew Demon, and prior to the a 3 gallon bucket. Every once in a while it would overflow into the airlock and thus a small PITA to clean. I usually run a hose into a jar to handle overflow. Now I use poppets in a pressure lid with a spunding valve set up that relieves pressure at about 2-5 psi and that keeps the Krause below the lid.
I account for a quart loss so I am putting 2.75 gals. I would think 2 gal batch would provide the extra headspace in a 3 gal bucket. Keep a second airlock and a sponge on hand just in case for a fast and easy clean up