Crash cooling a carboy without an airlock

[brewerTristan]

What is the likelihood of my beer getting oxidized if I leave it in a chest freezer at 40F with just aluminum foil covering the top of the carboy? I'm doing this because it doesn't fit with the airlock attached. I would usually just do a blow off tube, but it seemed unnecessary since fermentation is over. I've put it in there now, but will gladly take it out or manufacture a blow off tube, if the beer is at risk.

[seanhagerty]

I think you will be ok with the foil over it.

[BadRock]

That's usually what I do. If you have an air lock or blow off tube attached you will suck in water from your blow off buck or air lock due to the rapid temperature change.

[brewerTristan]

Ah excellent. Good tip from Badrock too. I remember reading about that now.

[Lars]

It should be fine. Just remember that co2 is heavier than air, so you should have a blanket of co2 over your beer even if a bit of air gets in there.

[noremorse1]

I would say you are fine. I would just make sure the foil is pressed tightly... tight like a tiger.

[dresselbrew]

Sometimes I use saran wrap and a rubber band. That will seal it up fine. They make silicone stoppers that have a flap on them so they don't build up pressure. I've been contemplating getting some of those as well. Either NB or B3 sells them, I can't remember.