Oxygenation and crash cooling

[bwhite3]

I got a beer back from a comp to learn it has oxidation problems. It was hard for me to detect because it was hoppy and dry hopped. Once it was pointed out I realized it and saved a few bottles to remind me of the flavor (papery, cardboard)

I ferment in a 9 gallon fermenter bucket with spigot. I tenp control the fermentation and crash cool after a D rest. So, when we crash cool , I remove my airlock and replace with a foil piece because it will "suck" air as the liquid cools. (Removing airlock to avoid Star San getting sucked in)

So, say I like it crashed for a week - it pulled oxygen in the fermenter but I was hoping there would still be a layer of O2 on top of the beer. I purge the keg with c02 before I rack to carbonate. Breweries would replace fermenter headspace with co2 as its cooling (I think) but what do we do?

 

[Hammy71]

I always secondary when I dryhop. I will purge the secondary with CO2 before I transfer. When it comes time to crash cool, I will put more CO2 on top of the beer before I crash cool. This ensures there is a blanket and any suction will hopefully only be CO2. That's what I do at least. I have noticed a difference in my IPAs since I started doing this.

 

[cosmo]

I don't "Crash" cool in the primary just for this reason. I leave the blow off tube in and don't switch to an airlock unless I go to a secondary. That way I can monitor the liquid level in the tube. I drop the temp slowly a few degrees a day and make sure the star san isn't getting sucked into the fermenter. I also make sure there is very little headspace in the secondary if I use one. The other option is to secondary in a keg, then transfer to another keg by pushing it with CO2.

 

[IL1kebeer]

Transfer to keg right after d rest and crash cool in the keg. No chance of pulling in oxygen from cooling if the headspace of the keg is purged.

 

[ArcLight]

>>So, when we crash cool , I remove my airlock and replace with a foil piece because it will "suck" air as the liquid cools. (Removing airlock to avoid Star San getting sucked in)

Why not just use an S-Type air lock? That lets in the air when it cools, but the Star San wont get sucked in. And you still have the seal. You could even nudge the bucket to release some dissolved CO2 to expand the gas volume in the head space.

 

[cosmo]

I'm not sure which is worse in the fermenter, Starsan or Air. I avoid both.

 

[cuda6pak]

If it's just a bit of starsan getting sucked into 5gallons of beer, who cares?

 

[daksin]

I'm not sure which is worse in the fermenter, Starsan or Air. I avoid both.

That's an easy one. Air.

 

[ICWiener]

I fill the arilock with vodka, that way I don't care if a little gets sucked into the beer. When crash cooling, I just check in every hour to top off the airlock so that air never gets pulled in.

PITA, for sure....but that's also why I don't crash cool anymore.

 

[bwhite3]

I was so excited for temp control and the ability to treat my fermenter as a faux "uni-tank" and crash to near freezing for several days (or lager for extended periods) in the same fermenter.

Maybe ill get to S lock. I didn't know that had that benefit. Topping up the airlock every hour sounds annoying. It usually takes 36 - 48 hours for me to drop from 68-69 (D rest) down to 33F.

Damn that sucking air in! I wish I had a fermenter that could hold pressure, then I would top up with C02 and carbonate in there as well. Hmmmm. :rockin:

 

[IL1kebeer]

Why are you not considering crash cooling in a keg? Any reason why you want it to be done in the fermenter?

 

[PLOVE]

I fill the arilock with vodka, that way I don't care if a little gets sucked into the beer.

+1. And pour it in the fermenter before kegging/bottling.

 

[cosmo]

Either vodka or starsan are fine in an airlock, but that't not the point. You can't drop the temp down to near freezing in a primary and not expect to suck a bunch of air in. Pulling in a quart of liquid or air (whatever is available to the fermenter) is not uncommon. You need to either go very slow dropping the temp while keeping an eye on it, or go with a secondary with very little headspace, or keg. If you use an airlock on a primary and crash the temp, you are only fooling yourself. A lot of air is getting in while you are not looking.

 

[Dolomieu]

Why are you not considering crash cooling in a keg? Any reason why you want it to be done in the fermenter?

^^ this. I cold crash in one keg while carbing then transfer under pressure via spunding valve to the next keg. Sometimes i dry hop during that time.

 

[rustym]

I crash cool all the time and never have suck back with an S-type airlock.

 

[tagz]

I just put a solid stopper in. Sometimes I use a piece of sanataized Saran Wrap under my airlock stopper. No suck back, no air. I do it with glass or BB. The better bottle contracts a bit, but no big deal.