• Please visit and share your knowledge at our sister communities:
  • If you have not, please join our official Homebrewing Facebook Group!

    Homebrewing Facebook Group

Carboy overflow and airlocks

Homebrew Talk

Help Support Homebrew Talk:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Mechphisto

Well-Known Member
Joined
Dec 28, 2012
Messages
68
Reaction score
2
So until now I've always used I think 6.5-gallon fermentation buckets for 5-gallon batches, and used an airlock and never worried about overflow.

Now, I'm given a 5-gallon glass carboy as a gift. And I'm thinking, especially as I've Googled "carboy overflow" images, that an airlock is a bad idea and I'm going to have to go with an overflow hose.

Sucky thing is (to me) and this may sound weird, is I really only have the space for just the carboy in the garage, having a bucket of sanitized water next to it for a hose is awkward. But, is that really my only choice? There just really is no headroom in a 5-gallon carboy for a 5-gallon batch, to just use an airlock, is there?

Thanks for any feedback.
Liam
 
I think you have 4 choices:
- juggle space to fit a blow-off bucket.
- use fermencap to suppress the krausen.
- trade it in for a 6.5G carboy.
- keep it for secondary/aging.
 
Brew a 4 gallon (or 3 gallon) batch?

I have generally always used prepared extract kits from the homebrew store, those are set up for 5-gallon batches. It's really not possible to use those kits to just make 4 (or especially 3) gallon batches is it? (I mean, aside from the lost number of bottles of beer per batch which is a shame in its own right), the recipe assumes 5 gallons of water to get the taste it's going for... using a gallon or two less water would just through it all akilter, right?
 
Can you go vertical to make room for a blow off bucket? Just a quick description. Blow off bucket is hung above the fermentor. A large volume bucket which will never fill preventing suck back. Blow off tube goes in through the lid. An airlock is also installed in the lid to release pressure and prevent a vacuum.
 
Correct, it's not practical to scale pre-packaged extract kits. Batch size flexibility is a benefit of brewing AG or extract using recipes you plan on your own. You could always use the 5 gal carboy as a secondary for any kits that include fruit, lots of dry hops, or other additives (or aging).
 
Similar to what flars described but lower tech... Put the carboy in a milk crate, blow off tube through the stopper into a 1L plastic soda bottle with some star san in it. It will fit snug between the carboy and crate. Just check on it every day so you don't have overflow of the overflow. This is what I do and the benefit is that it blows off plenty of crud that would just drop back into your beer. You'll lose a bit to blow off but you may find you end up with a better tasting beer.
 
Similar to what flars described but lower tech... Put the carboy in a milk crate, blow off tube through the stopper into a 1L plastic soda bottle with some star san in it. It will fit snug between the carboy and crate. Just check on it every day so you don't have overflow of the overflow. This is what I do and the benefit is that it blows off plenty of crud that would just drop back into your beer. You'll lose a bit to blow off but you may find you end up with a better tasting beer.

Holy cow that sounds brilliant!
What size hose do you recommend?
 
I use a 3/4 hose and a half gallon milk jug. that works well for me, but I rarely use whole hops. If you're at all concern about hops getting stuck, Shoot for the biggest hose your carboy and over flow jug can take.

You'll be happier without a tone of headspace once I figure out the blowoff rig. Plus you ca watch the action through the glass.

Also heads up, if your beer starts to cool after active fermentation it might start sucking the blow off mess back up. So swap out to a standard air lock once your Krausen starts to fall.
 
Also heads up, if your beer starts to cool after active fermentation it might start sucking the blow off mess back up. So swap out to a standard air lock once your Krausen starts to fall.

whoa, good to know! Thank you!
 
Holy cow that sounds brilliant!
What size hose do you recommend?

I use 3/8" just because it's what I have and with a 6.5 or 7 stopper, I can get the hose through the hole. Takes a little pressure, patience and hot star san to make them marry. You may find you can get a bigger soda bottle in that space which is even better.
 
Last edited by a moderator:
Back
Top