[klickitat jim]

I think the schedule isnt as import as a few key principles. 1: Pitching at or below the target temp. Yeast in dropping temps may tend to get a bit lazy so starting low and going up prevents that. 2: Starting your D rest climb before the beer is totally attenuated. Again to prevent them from getting lazy too soon. 3: going by gravity readings rather than a calendar. Its a gravity and temp thing not a time thing. 4: cold storage with carbonation. I can't think of a lager style beer that wouldn't benefit from a few weeks aat sub 40º once it is all done.

[brewinhard]

U shaped airlocks will not suck back, three piece and blowoffs will. I use sold stoppers when I cold crash with better bottles.

An S-shaped (u) airlock will not suck back, but it does allow oxygen to ingress into the fermenter as the beer starts to cool and the headspace cools creating a pressure difference which will pull air into the fermenter from the outside.  Negligible amounts of O2...perhaps?  But if you are truly concerned, then after your diacetyl rest, rack to a keg before crashing. 

[klickitat jim]

U shaped airlocks will not suck back, three piece and blowoffs will. I use sold stoppers when I cold crash with better bottles.

An S-shaped (u) airlock will not suck back, but it does allow oxygen to ingress into the fermenter as the beer starts to cool and the headspace cools creating a pressure difference which will pull air into the fermenter from the outside.  Negligible amounts of O2...perhaps?  But if you are truly concerned, then after your diacetyl rest, rack to a keg before crashing.

I wonder about this in a chest freezer temp control chamber. It seems like most of the freezer would be full of CO2 by this point. It seems like the amount of O2 would be miniscule.

[Stevie]

U shaped airlocks will not suck back, three piece and blowoffs will. I use sold stoppers when I cold crash with better bottles.

An S-shaped (u) airlock will not suck back, but it does allow oxygen to ingress into the fermenter as the beer starts to cool and the headspace cools creating a pressure difference which will pull air into the fermenter from the outside.  Negligible amounts of O2...perhaps?  But if you are truly concerned, then after your diacetyl rest, rack to a keg before crashing.

I wonder about this in a chest freezer temp control chamber. It seems like most of the freezer would be full of CO2 by this point. It seems like the amount of O2 would be miniscule.

Yep. I have considered buying a snorkel for when I need to reach into the freezer to pull a carboy.

[HoosierBrew]

U shaped airlocks will not suck back, three piece and blowoffs will. I use sold stoppers when I cold crash with better bottles.

An S-shaped (u) airlock will not suck back, but it does allow oxygen to ingress into the fermenter as the beer starts to cool and the headspace cools creating a pressure difference which will pull air into the fermenter from the outside.  Negligible amounts of O2...perhaps?  But if you are truly concerned, then after your diacetyl rest, rack to a keg before crashing. 

Yeah, I always felt that whatever O2 gets sucked back in must sit on top of the heavier layer of CO2, or else a lot of people here would make a lot of oxidized beer from crashing. All the same, I still prefer to crash and/or lager in a corny.

[hopfenundmalz]

When you all say that you cold-crash, do you lower the temp gradually over a period of days?  Or do you set the temp controller to say 32-34F and cool it down in a matter of hours?  I read somewhere to not cool it down more than 5F per day, or you will shock the yeast. 

I just did my second lager, and I cooled it gradually.  I'm just wondering if I'm wasting time for nothing.

If you perform a d-rest and you had a healthy fermentation then your lagering is not really about letting the yeast clean up the beer at cool temperature over a long period of time but just getting the beer to drop clear. In that case it doesn't matter how fast you cold crash. On the other hand, if you are relying upon the traditional lagering approach then you would want to adopt a slower schedule for chilling to 32F.

This is what I have said often. Somewhere I read that crashing too fast stresses the yeast, and they give off esters and other flavor compounds. As a homebrewer, I will try to go down about 4 degrees F or less a day and see if that does any good. My lagers are generally good, just seeing if I can make them better!

[klickitat jim]

I think Zainashef mentioned a study that reported an increase in esters by crashing vs slow drop. But he didn't reference the study. Im not saying he invented it but it might be that the exact details of what "they" did in the study could reveal wether or not it even applies to us. Like what yeast, what gravity, what temps, grain bill etc etc.

If you cold crash and don't experience a problem it seems to me that it doesn't matter much what we've heard.

It has been my experience that so long as the yeast are all done doing their jobs, it doesn't matter much if I drop slow or fast. Dropping fast might actually creat a clearer product. Also it might help with viability since you're not taking several days to get it chilled, and getting that yeast into storage or reuse.

[jmitchell3]

What about a schedule for folks who bottle-condition beer?  I've never done a lager, but I'd like to but I bottle-condition. 

Could I pitch cold, ramp to ferm temp, raise for d-rest, crash back to <50F, bottle, condition at room temp for 3 weeks, then lager in the bottle for 3-4 weeks?

[morticaixavier]

What about a schedule for folks who bottle-condition beer?  I've never done a lager, but I'd like to but I bottle-condition. 

Could I pitch cold, ramp to ferm temp, raise for d-rest, crash back to <50F, bottle, condition at room temp for 3 weeks, then lager in the bottle for 3-4 weeks?

yes you can. you can skip the crash to 50 or crash and lager on the yeast at 32 and then transfer to the bottling bucket intentionally picking up a bit of yeast cake in the transfer.

[erockrph]

What about a schedule for folks who bottle-condition beer?  I've never done a lager, but I'd like to but I bottle-condition. 

Could I pitch cold, ramp to ferm temp, raise for d-rest, crash back to <50F, bottle, condition at room temp for 3 weeks, then lager in the bottle for 3-4 weeks?

yes you can. you can skip the crash to 50 or crash and lager on the yeast at 32 and then transfer to the bottling bucket intentionally picking up a bit of yeast cake in the transfer.

+1 to skipping the crash after the D-rest. I have done exactly this procedure on several occasions before I had a fermentation chamber and was very happy with the results. Just make sure you check for carbonation before you lager the bottles.