What size primary should I use for 5 gal beer?

[abefroman]

What size primary should I use for 5 gal beer?

I have it in a 7.8gal now, should I switch to a 6.5, or is the 7.8 OK?

 

[rycov]

that's fine, the active ferment will push the o2 out of the head space. there is more concern with size of secondary than primary

 

[NordeastBrewer77]

Either's fine. I use a 6.5 gal carboy for a five gal batch.

 

[MrPat]

I would just leave it where it is. Unless you are adding fruit, dry hopping, or doing extended bulk aging, there shouldn't be a need to move it to a new fermenter. 5 gallons in a 7.8 sounds like a lot of headspace, but oxidation shouldn't be an issue as long as you don't keep it in there for more than a few weeks. You should purge the fermenter of oxygen w/ a blast of c02 if you have the ability to. Otherwise, don't worry about it.

 

[rycov]

5 gallons in a 7.8 sounds like a lot of headspace, but oxidation shouldn't be an issue as long as you don't keep it in there for more than a few weeks. You should purge the fermenter of oxygen w/ a blast of c02 if you have the ability to. Otherwise, don't worry about it.

the active ferment will push the o2 out of the head space.