If refrigerated, I would simply recommend warming up the beer for 3 weeks. I always hear claims that a diacetyl rest of ~3 days is adequate; however, this has not been my experience at all for dozens of batches. Instead, I find that the diacetyl is usually gone after about 2-4 weeks, average being 3 weeks.
I don’t get diacetyl with every batch of lager, but when I do, that’s how I handle it. No additional yeast pitch required. Krausening with fresh yeast might accelerate this, but… I’m a patient man.
For the record I have a beer on tap right now that had a touch of diacetyl. I moved the keg upstairs and put it into a warm closet for about 1 week. The moving of the keg roused the yeast and every 1-2 days I would just pull the release pin a bit. After a week I connected a cobra tap and the diacetyl was gone and the beer was a bit flatter than it should be. I put it back into the draft fridge and checked it daily and after 3-4 days it was carbed properly again. This is my standard “remove the D” process and I supposed YMMV. It has never taken me 3 weeks but I suppose it depends on the conditions, variables, amount of diacetyl, etc. I have never had to repitch yeast to remove it.
This is what I do. I just check the warm beer every few days until it is clean. I think there are times when krausening is necessary. I think that’s probably where Bel Air is right now.
That’s what we are thinking. Going to do another taste test today with a friend, to determine the best approach.
Need to clean this beer up soon as I would like to take the keg to a Christmas Party.
I brew a lot of lagers and rarely get any VDK/diacetyl, but I do perform a D-rest. The D-rest shouldn’t take more than a couple of days, but I’m sure it could vary from strain to strain. If you keep having a VDK problem, adding yeast after the fact is a band-aid approach, there is something wrong in your process. Aeration rates, pitch rates, yeast health and yeast strains all have an impact on VDK production.
I don’t like diacetyl in my beer either, the problem I have is that I’m not that sensitive to it. So when I send it off to a competition I’m not 100% sure I got rid of it. So now I add ALDC at pitch to eliminate any butter aroma/flavor. I never really had much of a problem, but the ALDC adds some level of assurance that I don’t have it in my beer. More Beer carries it. I can get @ 20-25 batches per bottle, which is about a years worth for me. It’s a little pricey, but if it saves one beer or gets me one more medal, it’s worth it.
It’s targeted toward Hazy IPA’s to reduce VDK from hop creep, but many lager brewers, both pro and amateurs alike, are adding this at pitch.
EDIT: I believe it can be added post fermentation too, it just has to be mix into the beer well.
Yes, I agree it’s a band aid approach. My brewing process is pretty meticulous, with an emphasis on sanitation. Not saying my process is perfect.
A D-Rest is always employed.
Just won a Gold at the Dixie Cup for my Irish Red. One out of three judges commented on diacetyl. The other two never mentioned it, or any off flavors.
I will let lagers sit in a fridge for 4-5 days and eventually bring the fermenter out of the fridge where it rests at room temp. When the weather is warmer, everything works as it should. When it gets cooler, that time sitting at room temp is (sometimes) not warm enough to remove the diacetyl. So I have a system in place to deal with it but the system needs an adjustment based on season. What is the magic temp to remove diacetyl? Is there one?
There isn’t a magic temperature for a d-rest. It requires the yeast to be active and in suspension. The warmer temperatures increase the metabolic rate of yeast and that causes the the diacetyl to clean up quicker. Healthy yeast can do this in their normal temperature range, but it requires them to be active. Flocculated yeast is unlikely to have much of an effect on diacetyl/VDK levels. It’s best to perform a d-rest during active fermentation just prior to reaching final gravity. For ales there really isn’t much to do, for lagers raising the temp 10-15F can speed things up.
+1 even new approaches to lager brewing (pressure fermenting, for example) can benefit from a little lagering (in serving kegs or bright tanks) than with typical ales. Ultimately, though, pitching sufficiently healthy (not too many re-pitches) and freshly harvested (from fermenter to pitch on the same day when possible) yeast avoids diacetyl build up in most instances in my experience. YMMV, of course.
If you want to explore other chemically enzymatic additive approaches to cleaning up diacetyl there is the Alpha Acetolactate Decarboxylase (ALDC) route:
people have said a lot of solutions and prevention tips for next time. if i were you and you want a beer that is extremely good for your friends and the due date was dec 20 or later, i would just start fresh, i think you have some decent temp controls. correct size starter or dry packets, start cold, ramp temperature according to the fast lager ferment schedule people often do nowadays, stay at ~60 to 62 or whatever is recommended after ferment is complete for 2 to 4 days. cold crash it and let it sit for as long as you’d like at cold temps until a week before you keg it.
you still have time for this for sure. a “fast lager” schedule does not mean a bad fermentation at all, i think the vast majority of brewers who have tried it find it great.