Cold Crash - Pressure Question

[SowegaBrews]

I love this site, even when I can't find the answer to my specific question - I learn tons of new general knowledge about the subject just by looking for the answer myself...

So anyhoo, here's my question.

When you guys cold crash, what do you do about the water in your airlock?

Say you have an ale you've been fermenting at 65/68*F for 10 days (I'm in a rush) and notice no more activity, so you decide to cold crash before transferring to a keg. How do you keep the water in the airlock from being sucked into your beer? Thanks to the airlock, the fermenter pressure is equal to the atmosphere. When it begins to cool, the pressure is going to drop inside the fermenter, and the only way to equalize is by sucking whatever it can through the airlock. Is the resulting lack of seal (when all the water has been sucked in) a risk of oxygenation, or contamination?

 

[cvstrat]

For the water in the airlock use water/starsan mixture or vodka. Either one is sterile and won't harm the flavor of your beer. As for the actual answer to your question I have no idea, but w/proper airlock sanitation its a moot point.

edit: I seriously doubt it would suck all of the water back in, if any.

 

[Yooper]

Oh, dropping the temperature does cause suck-back. When you drop the temperature, just take off the airlock and either use a carboy cap or a piece of sanitized foil over the opening.

 

[The Pol]

Oh, dropping the temperature does cause suck-back. When you drop the temperature, just take off the airlock and either use a carboy cap or a piece of sanitized foil over the opening.

+1

My fermentor has a screw on cap with a seal, so I remove the airlock and seal it up. Foil works on all fermentors though.

 

[bmckee56]

How about transferring to a cornie keg. Purge it with CO2 prior to filling and there is no need to worry about O2 (This is of course if you have a cornie available). If not, use the foil.

Salute!

 

[The Pol]

For the water in the airlock use water/starsan mixture or vodka. Either one is sterile and won't harm the flavor of your beer. As for the actual answer to your question I have no idea, but w/proper airlock sanitation its a moot point.

edit: I seriously doubt it would suck all of the water back in, if any.

It will suck the airlock dry... if going from say 65F to 35F.

 

[SowegaBrews]

How about transferring to a cornie keg. Purge it with CO2 prior to filling and there is no need to worry about O2 (This is of course if you have a cornie available). If not, use the foil.

Salute!

I have cornies available. I just figured I'd cold crash in my fermenter before I transferred to one to help clear it up a bit.

Thanks for the info everyone. I'll probably start cold crashing tonight.

 

[corncob]

I have noticed this phenomenon--dropping the temp from 70F to 45F will pull maybe a tablespoon in. And after listening to a podcast from the brewing network in which they mentioned that StarSan has a surfactant in it to help the foam wet all surfaces and may hurt head retention in large quantities, I wonder if this isn't responsible for the head retention problems I've had.

I always chill the fermentor (with airlock) for a day or two before kegging to speed carbonation. I sanitize the keg, rack, and shake like heck at ~25 psi until the hissing stops. Then I rest at normal pressure for about four days. It's been working well, except that the head on my beer seems overly "wet" and fades immediately.

It will be a month or so before I get any results for my first "starsan-free" brew--hopefully I can find and resurrect this thread.

 

[fartingdog]

I use and s-type airlock when I cold crash (learned my lesson w/3-piece and suck-back) filled with star san (cheap vodka would also do). Works very well, little or no suck back.