Lager: Crash Cool vs. Gentle cooling

So I am doing my second lager attempt, a maibock. I started with an OG of 1.070 and am hoping to hit a TG of 1.012-1.010. When I racked it the gravity showed 1.015, so I'm really close. It's finally done with primary and I just racked to a glass carboy at room temp for a diacatyl rest.

My question is what are the benefits of a gentle slope compared to just crash cooling? I have heard that if you don't do a rest, the slope allows the yeast time to continue processing their byproducts, but if you do a thorough rest and are force carbing (I am) that you can just crash cool and let it condition, as the yeast are sort of done with the job.

Any info would be great. Thanks!

If your done with the yeast crash them out. I've not found any draw backs doing it. The slowly cooling it down method is the old way that it was done. The beer carbonated as it lagered so it had to be cooled down slowly before it was at FG. The modern way is to use a temp ramp or diacatyl rest for faster maturation.

Great, this definitely helps with the space. I usually use my kreezer as a lager chamber, but it already has a pale ale force carbing in a serving keg.............don't really want to have to wait while I'm getting the temp back down

Ferment, d-rest and crash away!

One of the guys on the Brewing Network, maybe John Palmer or Jamil, suggested doing it when it is around 75% fermented. So 1.070 beer with TG of 1.010 = 60 points * 75% = 45, so 70-45 = around 1.025 gravity to do it at. A few days at the warmer temps will clean the diacetyl and help the beer fully ferment. I do not recall the reasons why they recommend that, but did try for my last lager and it came out great.

I have heard similar. And I may or may not have given in and tasted the maibock right before the crash...............and if I had I'm fairly sure that the rest cleaned up the diacatyl beautifully........I would know that only if I had done this of course....

Rise! Rise back to life!

As mentioned briefly here, there is some feeling that crash cooling can be hard on the yeast, even to the point of convincing them to start excreting substances that may not taste good (this is different from autolysis). For this reason, the logic goes, the crashing should be more of a ramp down.

Anyone actually have this "bad" experience with (unsought after) flavor effects of crash cooled yeast?

The key is to not crash cool until the yeast are "done."

I haven't lagered yet but I'm getting to it this winter. Anyways, when I have the time to crash my ales, I usually will do a 10F per day ramp down, only changing the temp once per day. Perhaps this will help someone...

Malticulous said:

The key is to not crash cool until the yeast are "done."

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That makes sense but I think the off flavors that practitioners of the no-crash method (ramp down) worry about come from yeast, either in suspension or that have floc'd out, regardless of whether or not their work is done. That is, they could just be chillin (he he) after hitting TG and then bam! someone throws them into cold crash at which point they get freaked out and excrete off flavors as they go into hibernation. But maybe the metabolic changes that occur when TG is hit limits excretion of off-flavors?

In any case, would be interesting to hear if a cold crash has led to off-flavors for anyone? Otherwise maybe a split-batch experiment is in order. But I suppose this only matter for impatient people--when in doubt, just ramp it down.

If you're going to lager the beer for weeks or months, I don't see what the hurry is in the cool down phase. You might as well spend a few days to a week cooling the beer down. I'm not sure I'd go to 2 deg F per day, but cooling at a rate of 5 deg F per day seems pretty reasonable (that's what I do when I cold-condition any of my beers).

My understanding from what I've read is that there's no real benefit from slow temp ramps when you're using typical homebrewing methods. There are some traditional German methods where fermentation is still occurring that you might want to slowly drop the temp, but if you're letting the fermentation complete and then lowering the temp for cold conditioning (like most every home brewer does), you can rapidly drop the temp with no worries. Or you could drop it slowly with no worries as well.

I crash. Mostly because I typically have several kegs at different stages of lagering and I don't want to slow down their lagering by raising the temps so the new kegs can ramp down.

pjj2ba said:

I crash. Mostly because I typically have several kegs at different stages of lagering and I don't want to slow down their lagering by raising the temps so the new kegs can ramp down.

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Me too, and I rapidly cold crash every batch. I simply move the primary out of the fermenter chamber directly into the cold crash/lagering chamber (which stays at 35-36*F).

I've yet to see any basis at all (either scientific or by my observations) for the belief that a few folks have expressed about post-fermentation fast cold crashing causing any yeast problems or off-flavors.

FarmerTed said:

If you're going to lager the beer for weeks or months, I don't see what the hurry is in the cool down phase. You might as well spend a few days to a week cooling the beer down. I'm not sure I'd go to 2 deg F per day, but cooling at a rate of 5 deg F per day seems pretty reasonable (that's what I do when I cold-condition any of my beers).

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For me, it isn't an issue of time per se, but the availability of cooling vessels at multiple temperature for multiple beers.