Diacetyl reduction post fermentation?

[Br3w4u]

Is it possible to reduce or eliminate diacetyl after fermentation is complete and the beer is in a keg? Could I leave it out at room temp with the PRV open? Would it ever go away if I store it my keeper long enough? Am I just stuck with a butter beer?

 

[shoengine]

From what I understand is diacetyl is a chemical compound in the beer, so venting it won't make it go away. John Palmer in How to Brew suggests repitching some yeast with an amount of sugar and ferment again around 65 F to have the new yeast perform some garbage collection on the existing diacetyl.

 

[Smellyglove]

If you have some LME or DME at hand, boil it, pitch some yeast, wait for krausen, then dump that miniwort into the keg at ferm-temp.

I've tried just taking a keg out of the fridge again into room temp once, didn't work.

 

[Br3w4u]

Would I need to use an airlock or can I just open the PRV during the fermentation? I would think it should only take a day or 2 at the most right?

 

[shoengine]

If you keep the valve open, you have the opportunity to introduce wild yeast and/or oxygen. Not sure what the liklihood of either though.

 

[Cool_Hand_Luke]

Would I need to use an airlock or can I just open the PRV during the fermentation? I would think it should only take a day or 2 at the most right?

You could unscrew the PRV and put some tubing over the port and take that to a jar of starsan. Like a mini blow off tube. Never tried it, but should work. Shouldn’t be nearly as vigorous of a fermentation as the initial one.

 

[Br3w4u]

You could unscrew the PRV and put some tubing over the port and take that to a jar of starsan. Like a mini blow off tube. Never tried it, but should work. Shouldn’t be nearly as vigorous of a fermentation as the initial one.

Ok thanks I will try that. Never fermented in a keg before.

 

[dmtaylor]

Keep it warm for 3-4 weeks, and pray. If there's any trace of yeast in there, it might go away with age. Yeast eats it. But if the yeast is sparse and tired, they might not eat it. Try it, and hope.

 

[Cool_Hand_Luke]

Ok thanks I will try that. Never fermented in a keg before.

I haven’t either but there are others here that have.

https://www.homebrewtalk.com/forum/threads/primary-fermentation-in-corny-keg.127876/

I was thinking about that pressure relief valve and it’s actually male and the nozzle on the lid is female. But 1/2” silicone hose fits nicely over it.

If your keg isn’t too full you could also just attach to the gas post and take that to a jar of starsan.

There are also those who ferment under pressure using kegs:

https://www.homebrewtalk.com/f13/closed-system-pressurized-fermentation-technique-44344/

Hope it turns out!

 

[couchsending]

Depending on how bad it is dumping a little wort at high krausen will clean it right up. You could also just do it under pressure and naturally carbonate the keg at the same time. Brewers friend has a priming calculator for krausening. Should probably only take a week to clean up and carbonate.