Glass carboy for 5g batches do i need a 6.5g carboy?

ohill1981 · 12-15-2008, 08:21 PM

Tomorrow i am planning on going to my LHBS and purchasing a glass carboy/air lock for a secondary fermenter. Since i will be leaving my batches of brew in a primary for 3-4 weeks i was looking to add a carboy so i can run two beer's at once. I was unsure though of what size of Carboy to look for if i am brewing a 5g batch. If i am brewing a 5g batch should i buy a 6.5g glass carboy? or a 5g? I know the less oxygen the better for fermentation but you also need room for the foam right?

By the way i wanted to say this forum has been extremely helpful and would like to give thanks to all the member's who have and who will help me out in the future !!!!

**PoorBoy** · 12-15-2008, 08:23 PM

from all the reading i've done, you want some head space for primary fermentation, requiring a 6 or 6.5g carboy

Deacon240 · 12-15-2008, 08:28 PM

All I've learned says 6.5g glass carboy for primary fermenting and even secondary. But a 5-6g carboy should be sufficient for secondary as typically that's a calm stage.

**conpewter** · 12-15-2008, 08:29 PM

6.5 carboy gives enough headspace for the krausen usually. Though now adays with the price of carboys you might be better off getting a 6 gallon better bottle or a 6-7 gallon bucket with grommeted lid

Ecnerwal · 12-15-2008, 08:31 PM

If you are buying "a second primary fermenter" where you are going to start and finish in the same container by leaving it there for 3-4 weeks, 6.5 gallon is good, and even that blows off sometimes.

A pail is cheaper, but I personally prefer glass as well. Given the cost differential, if I broke my big one at this point I'd certainly consider a pail at half the price, but I've had it for ~15 years and not broken it yet. Knock wood.

If you are buying "a secondary fermenter" (start in primary, move to secondary after a week or two) 5 gallons is fine.

dontman · 12-15-2008, 08:35 PM

I greatly prefer the 6 Gallon Better Bottle to a glass carboy but in any case I recommend 6 Gallon or better. You will lose some to trub some to blowoff and besides, with fermentation going on there is no oxygen in the carboy because it has been displaced with CO2. Headspace is only an issue in wine carboys that will be sitting for a year or more, and not even then really.

BTW, I regret both of my 5 gallon carboy purchases. It limits them to only secondaries

ohill1981 · 12-15-2008, 08:35 PM

I would like to go to use the carboy as a "Secondary fermenter", but i have read so often than using a secondary fermenter increases your chances of contamination and that it was not necessary for most beers, but i am still unsure

**PoorBoy** · 12-15-2008, 08:44 PM

Quote:

Originally Posted by ohill1981

I would like to go to use the carboy as a "Secondary fermenter", but i have read so often than using a secondary fermenter increases your chances of contamination and that it was not necessary for most beers, but i am still unsure

i use a 5g carboy for a secondary. not a lot of fermentation happens in there.
i use it to clarify. a lot of people don't use a secondary at all.

BrewHerc · 12-15-2008, 08:48 PM

I the Complete Joy of Homebrewing, Uncle Charlie uses a 5 gallon carboy, but attaches a blow-off tube until the krausen subsides. He then attaches the ferm lock.

BrewHerc

alpo · 12-15-2008, 08:48 PM

I use a 5 gal secondary and it works fine. If you time it correctly, there won't be a lot going on in the secondary.

I don't think you want a lot of headspace in the secondary (provided fermentation is basically complete) because the increased surface area can increase oxidation.

If you think you might want to use it as a primary one day, then you will definitely want the 6-6.5 gal.