Extended diacyal rest case study

I plan on moving my lager to 68° for this rest I hear so much about soon. In the process it frees up room in my kegger to ferment another lager. The one I am moving I am still considering tossing (see broken glass thread), but I really want to see how it turns out ultimately, so as long as I have room to keep it stored in some kind of vessel (which shouldn't be a problem), I'll let you all know how it turns out.

This way should someone ever find themselves in a situation where a lager has been left at celler temps prior to lagering I can answer them whether or not the batch is ruined.

Hypothesis is since the yeast will be pretty much done fermenting anyways, and most fermentables will be eaten I doubt there will be much of a problem.

petep1980 said:

...whether or not the batch is ruined.

Hypothesis is since the yeast will be pretty much done fermenting anyways, and most fermentables will be eaten I doubt there will be much of a problem.

Click to expand...

I wouldn't expect the batch to be ruined anyway. I would just expect the batch to have a different flavor profile than if it were actually lagered after the rest. I would predict a less clean, more esther-y profile.

cactusgarrett said:

I wouldn't expect the batch to be ruined anyway. I would just expect the batch to have a different flavor profile than if it were actually lagered after the rest. I would predict a less clean, more esther-y profile.

Click to expand...

Maybe I misunderstood, but I don't think he's skipping the lagering part. He's just bumping it up for a d-rest. He said "prior to lagering" ...

Anyway, that would be fine. Cellar temps won't hurt the beer. The IDEAL method, from what I've heard, is to pitch cool (say 45) then bump it up to ferm temps, so little or now diacetyl is created, and then go straight to lagering at the end of fermentation. No d-rest would be needed. This results in fewer temp swings, and a arguably a marginally cleaner profile. I do a d-rest in my beers though, to be sure, as I usually pitch about 52-55F.

However, your d-rest won't actually do anything unless there still are fermentables in the beer though. The idea is that the yeast use or reabsorb diacetyl when they are working. So if they aren't working, then there's little positive effect to a d-rest.

Well, I clearly don't know which way is up anymore. It's just going to cellar pretty much until I kill a keg of APA, and the other o-fest is done fermenting.

So if I pitch around 45, then turn the kegger up to 55 I can skip this rest? (curious for future batches).

I think i'm starting to figure out more what you've got going on. I think it depends on how long and what temp you primarily fermented at, as WorryWort suggested. If you're fermenting around 55F, (assuming that's on the high end for your strain) you're more likely to need a d-rest. Provided you didn't produce any diacetyl, you shouldn't need a rest, though.

That being said, if you did have any diacetyl, I would have no problem leaving the batch on "extended d-rest" around 55. Issue with that, though, is that it would take longer for the yeast to clean up after themselves than if you did a d-rest at 60F for a few days (more of a typical temp for d-rest). This, also, is provided your yeast were still active (say, if the d-rest was performed after you've reached about 75% complete fermentation).