View Full Version : Blasting a Carboy with CO2

02-11-2004, 07:59 AM
Now, what's the deal with taking the oxygen out of a carboy with CO2?

I've talked to some serious homebrewers and they do this all the time, but I haven't found anything on this site about the procedure.

Is this personal preference or necessary?

02-11-2004, 07:09 PM
If you have the CO2, a home kegging system maybe, then it is under the category of things that can't hurt, I'm actually looking into a machine that racks and bottles by creating a Vacuum un the destination bottle/carboy.

02-12-2004, 01:56 AM
absolutly not necessary. it certainly would not hurt, however, it goes under the heading of advanced topics. its just one of those things you can do to make the process more complicated. heres an idea...how about clearing the air out of a carboy using the CO2 generated from an alwready fermenting batch?

02-12-2004, 03:57 AM
That is a neat idea. Sounds like more trouble than it's worth, but I wonder how you would do it.

02-12-2004, 05:29 AM
First of all, it would be less reliable, but the way to attempt it is rather easy. you need a tube attached to an airlock (I'd still use arilock first). you need a stopper for the empty carboy with two holes. run the blowoff tube from the carboy in process through the stopper to the base of the new carboy, put an airlock in the other hole.

Personally I prefer to sterilize the carboy immeadiately before use. I wouldn't choose the tradeoffs this scenario presents. If I already had a CO2 system for kegging, then tapping that would be simple im-mead-iately before racking and cost you only a little gas.

02-12-2004, 06:35 AM
there are carboy caps that have two holes on top...one hole is for attaching an airlock and the other is to attach tubing to use as a blowoff valve. you take the tube from the alwready fermenting batch and attach the other end to the cap of the new batch...then you stick a airlock in the second hole in the cap of the new batch. I know it sounds confusing, i hope you can visualize what i'm saying. this allows you to do two things. first off all it flushes the air out of the new carboy with the carbon dioxide being produced by the old carboy. and second if you use a batch thats in high krausen as your source you can actually use this set up to automatically pitch your new batch with highly active culture from the fermenting batch (as the krausen gets pushed into the blowoff valve). am i making any sense at all?

02-12-2004, 11:42 AM
Essentially the same method i described, except for the addition of blowoff and possible pitching.

Personally this isn't anything I'd do myself. I see real marginal value here outweighed (IMO) by multiplied risks. I'm not saying the riskers are large, just larger than not trying all of this. If batch 1 is infected with something that can compete with wine yeast, it would spread with the yeast to batch 2 during blowoff. While I haven't had infections to date, i sure wouldn't want to encourage one to spread.

I don't sparge with CO2 or N, If I did I'd prefer a more controlled method (Big pressurized Gass canister). Personally I'm far more likely to buy an ENOLMATIC BOTTLE FILLER


for $300 or so and let vaccuum pressure minimize oxidaion in racking, filtering and bottling. But this too is a luxury I haven't indulged myself with yet.

02-12-2004, 05:30 PM
It occurs to me that one aplication of this CO2 idea--whatever the source--might be if you are aging mead in a carboy that is too large for the volume you've got left. Say you have a batch that started off as five gallons, but you've racked and sampled it a few times and it's down to 3 gallons. It's basicly done fermenting, so if you don't have a smaller container for it, you might want to try something like this to get rid of that two gallons of air.

02-12-2004, 05:37 PM
I agree with you 100% Thirsty Viking. Its not a great setup, i've done it once or twice as an experiment but the benifit gained is certainly marginal. I was just presenting it as a possibility, and definately would not suggest it as an everyday procedure.

And to respond to your comment TeaTruck...that is exactly what i used this method for...a 5 gallon batch of mead that had been depleated to about 4 gallons and i used an activly fermenting (but not krausening) batch to blow the air out of it.

02-13-2004, 01:28 AM
That makes more sense than using it to pitch a culture. The alcohol in the bulk aging process would help protect against infection.