Slow cold crash to reduce oxygen ingress?

[David Woods]

I like to cold crash my beers to clear them up a bit but have been a bit concerned about oxygen being sucked into the fermenter - old school here, no pressure fermenter!

Just read a recipe on the Malt Miller site that says to cold crash slowly over 3 days to reduce oxygen/air being sucked in. The recipe had a high amount of dry hops - 100g - so that may be a reason.

Any thoughts on this? anyone do this? My fermentation fridge takes a while to get down to cold crash temp anyway - over a day - in fact the best I can get is 5c and I can't say I have noticed any affect from oxygen but then not an expert and as long as it tastes good with alcohol I am happy but also looking to improve things.

Dave

 

[Agentgonzo]

The amount of oxygen ingress is determined by the change in temperature. As the temperature drop, the wort/air contracts (a bit) but also the existing CO2 in the headspace is more soluble in the wort at lower temperatures. So that's why you get the oxygen ingress. It doesnt' have anything to do with the rate at which you cool - fast or slow, the same amount of air should be sucked in (theoretically). I can't see any reason why they would be advising to cool slowly to reduce the air being sucked in.

 

[Sadfield]

Cooling slower is better for head retention. Crashing anything is never good.

 

[Druncan]

I have a 20l l wine/cider bag that I fill with co2 as the fv is chilled it gets sooked back. I use the same method when kegging. I also pressure ferment and use the created pressure is used as the FV is crashed(sic) fast as fook with my glycol chiller.