Spike Brewing Giveaway - New v3 Kettle

Home Brew Forums > Home Brewing Beer > General Beer Discussion > Cold crash question
Thread Tools
Old 04-01-2013, 02:47 PM   #1
Feedback Score: 0 reviews
Join Date: Feb 2013
Posts: 115
Liked 14 Times on 6 Posts
Likes Given: 11

Default Cold crash question

So I am cold crashing for the first time , and the airlock is moving in reverse sucking air back into the carboy. I understand the physics of it but don't like it. It is obviously sucking air with O2 back into my carboy. I suppose since CO2 is heavier than air, there will still be a blanket of CO2 over the beer to stop oxidation but it feels wrong. Any opinion/experience out there. Should I have done something else?

Thanks, t

trapae is offline
Reply With Quote
Old 04-01-2013, 03:55 PM   #2
Feedback Score: 0 reviews
Join Date: Apr 2012
Location: Schenectady, New York
Posts: 913
Liked 113 Times on 92 Posts
Likes Given: 307


How much air depends on the amount of headspace.

Air on average will lose about 4cc of volume per liter for each 1 degree drop in temperature.

If you have 1 liter of headspace in your carboy and reduce the temperature from 65 to 35 you will be sucking in about 120cc (4ounces). As to the effect this will have I do not know.

Less headspace means less suck back.

Hope this helps??


boscobeans is offline
Reply With Quote
Old 04-01-2013, 07:34 PM   #3
Feedback Score: 0 reviews
Join Date: May 2011
Location: Stow, MA
Posts: 15,335
Liked 2318 Times on 1777 Posts


I think the whole "blanket" thing is a myth, and the air will diffuse into the CO2/vice versa, which supports the notion of keeping a minimal headspace.

day_trippr is offline
Reply With Quote
Old 04-01-2013, 07:40 PM   #4
Feedback Score: 1 reviews
Join Date: Dec 2010
Location: Santa Monica, CA
Posts: 2,412
Liked 170 Times on 126 Posts
Likes Given: 533


i started using a solid bung to plug the lid in my bucket when I cold crash

i left the airlock on for many batches though and never noticed any oxidation etc, 5.25gal batch in a 6.5gal bucket
terrapinj is offline
Reply With Quote

Thread Tools

Similar Threads
Thread Thread Starter Forum Replies Last Post
cold crash question! RippinLt Beginners Beer Brewing Forum 5 02-01-2011 10:56 PM
Yet another Cold Crash question grimeey General Techniques 4 01-13-2010 08:25 PM
Cold Crash Question jesutton3 Beginners Beer Brewing Forum 4 06-18-2009 10:27 PM
Cold Crash Question coolkid102938 Beginners Beer Brewing Forum 1 06-11-2009 11:20 PM
Cold Crash Question sean6247 General Beer Discussion 1 03-19-2009 09:23 PM

Forum Jump