Headspace

[LostHopper]

I'm brewing a 2.5 gallon test batch
My only available fermenter is a 6 gallon bucket. Is 3.5 gallons of headspace a problem? I'm thinking it's not a problem.

I could probably borrow a 3 gallon carboy and deal with the blowoff but I'm going to be gone during some of the early fermentation time.


Update: Ignore. HBT "search" did its job.

 

[FVillatoro]

It will be a problem if you let it sit there after fermentation is finished (say more than 2 weeks).

The excess headspace can reduce the blanket of co2 that helps keep bacteria and mold out, and allowing them to take hold inside the fermenter.

I would keg/bottle within 2 weeks, if you chose to use that fermenter.

 

[kh54s10]

Oxidation is much more of a concern that bacteria or mold. If you are sanitary and don't leave the bucket open too long it should be ok. I would watch for fermentation signs to end wait a couple of days then bottle it.

The "blanket of co2" will start mixing with oxygen as soon as more co2 is no longer being created.

 

[JONNYROTTEN]

Pretty sure the whole "blanket of co2" which was the reason you couldn't move a fermenter as you would "disturb" the blanket was proven completely false...I stuck a match in a fermenter right near the beer level once and it laughed at me.

 

[LostHopper]

No worries.
I cut the batch to 2 1/4 gallons and used a 3 gallon glass carboy. That extra quart of head space may not be needed but I felt better about it.