have you ever noticed whether or not cold crashing in the fermentor oxidizes your beer?
What is your thinking on this? Possibly dropping the temp will suck o2 in?
Exactly.
I guess one way to remedy this would be to transfer to keg and pressure it with co2 .
I’ve noticed zero oxidation by cold crashing my primary. Though I suppose there is some infinitesimal amount, but not as much as opening the lid to take a gravity reading or to rack.
yeah, oxidation reactions are going to occur very very slowly when everything is cold so even if o2 is introduced it’s not going to be noticeable very quickly at all.
+1. Or if you start splashing it around…
Dave
Plug your fermenter with a solid stopper.
I use these with my better bottles.
http://www.williamsbrewing.com/10-VENTED-SILICONE-STOPPER-P2667.aspx
I prefer to rack to keg, top off with CO2, then crash and charge at same time.
I have not noticed an issue, but I only crash my lagers in the primary so the temp difference is much smaller and the amount of O2 getting in is probably very small as well.
+1
Paul, are you experiencing some off flavors in your beers?
just a little bit- my latest IPA is not quite as hoppy in aroma as usual, though not what I would consider oxidized.
I’d just read another brewer, whom I respect, being very OCD about crashing his IPAs and how he feels he oxidized one by crashing with too much head space in the fermentor, which got me thinking.
Lately, I’ve been crashing in the primary on a lot of beers to get the cleanest/clearest beer possible in the keg, but maybe I will go back to transferring to a keg, dryhopping and then crashing/carbing.
I usually blow some co2 into the headspace before I bung the carboy and cold crash. I don’t think it causes any issues, but I can see where you’re coming from. Got palate fatigue? 
By the time I’m cold crashing, whatever vessel I do it in is sealed. There’s no chance for O2 to enter.
I’ve gotta say that explanation doesn’t make a lot of sense to me.
i guess he feels the suck back as the beer cools brings in oxygen into the beer. I’m having a hard time figuring out if this is really a problem or not - hence why I’m posing the question to the collective wisdom of the forum.
air does vacuum in through the airlock. i do have a couple of those stoppers like steve linked above. maybe I should just use those…
the air is still gonna get in when you remove the stopper. I just can’t imagine it’s a big deal but it should be easy to test with a split 10 gallon batch, half kegged then crashed the other crashed then kegged.
to be fair you would want to wait say 1 month after kegging to see if there is actually any difference.
Yeah, but why are you using an airlock when you cold crash? Fermentation is done, there’s no need for it. I either keg to cold crash or seal the fermenter.