Diacetyl rest after lager period

So I lagered for almost 2 months after doing a diacetyl rest in the primary for 2 days at about 63F and it still came out with a butter flavor from diacetyl. What can I do to salvage this beer? Can I bring it to room temperature, pitch more lager yeast (34/70?) then let it sit for a week? Anything else I can do or is this beer simply not salvageable? TIA

If you keg, you can run some co2 in through the out tube and purge it a few times a day. It takes time to work. This was suggested to me and I haven't tired it myself.

Won't hurt to try I guess. Thanks.

I had decent luck throwing some nottingham yeast in a diacetyl bomb lager once. Just brought to room temp, threw the packet in, waited a few days, resume lagering. It wasn't a total fix, the beer was still "flawed", but it made it drinkable.

I have two kegs of diacetyl beer after lagering. What I did is to bring them out to room temperature, made a 1 qt starter with Pilsen DME and W34/70 and pithed half of that at high krausen in each keg. Its still fermenting right now and I pulled samples after two days, one is clean and other still has just a toch of smell, weird I can smell it but almost no taste so I think results will be good in couple more days. Its good news because I have two more lagers coming up both with diacetyl.

In a normal (not infected) fermentation diacetyl is formed when acetolactate which leaks from yeast cells is subject to non biologic oxidation after the beer is packaged. The only way to get rid of it is to expose the beer to living yeast after fermentation is complete. The yeast take up the diacetyl and reduce it to the much less flavorful acetoin and 2,3 butane diol.

Proper lagering or conditioning should control diacetyl or it can be controlled by means of diacetyl rests or addition of a portion of krausen beer provided that the acetolactate/diacetyl levels are normal. Something that is describable as a "diacetyl bomb" represents levels above normal which are probably caused by an infecting organism. I'll also note that I have been given several "diacetyl bombs" which were actually acetaldehyde bombs. The cause of this is also infection (different bugs though).

Bottom line is that exposure to live yeast is the only way to clean up diacteyl (actually, reduction with bisulfite works too but the beer still tastes awful - just not diacetyl awful) but this is only effective when infection was not involved. If it's a "bomb" it's proably no fixable.

having tried krausening a few times, it does really work well in lagers.

PaulHilgeman said:

having tried krausening a few times, it does really work well in lagers.

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it works so well that in fact I will krausen/carbonate all of my lagers in kegs after lagering period is over and don't even bother with diacetyl rest since I found it to be useless on several occasions.

Agreed, it makes the end result better faster and maybe just simply better.

I am very happy to report good results. As I mentioned in a previous post, my lager was a buttery bomb and I thought the beer was salvageable. I took the keg out of the keezer and was planning on dumping it. Well, I got really busy at work and it wasn't untill today that I finally got around to mess with my presumably ruined lager. I noticed that the keg was still pressurized when I relieved the vent valve on the keg. Just for snicks I decided to sample it. Low and behold, no noticeable diacetyl. I was shocked. I decided to place it back in the keezer to cool down. Just tried another sample now and it's still fine *and* properly carbonated to boot! It seems that the extended diacetyl rest period of over 2 weeks did the trick. Evidently, there was still enough yeast to clean things up. I plan on getting another freezer to use as a fermentation chamber for future lagers. All was not lost. I hope others learn from my experience. Cheers!