Diacytel Stratification

[rdkopp0153]

Weird question. I take a wine thief sample from the top of my German Pilsner in the keg and it's tastes great, noble hops, pilsner malt, but when it's run through the line it has a heavy diacytel taste? It's only been the first few pulls of the keg, so maybe I'm tasting yeast too?

 

[day_trippr]

This may just be one of those RDWHAHB moments.

Yes, if you don't do something to drop the yeast out of the beer prior to racking to a keg, the first few pours can be quite misleading as to the true character of the beer.

As for the diacetyl note (if that's actually what you're picking up), that could be something else again. Diacetyl can be produced by causes other than insufficient boil-off...

Cheers!

 

[rdkopp0153]

I was under the impression that diacytel is either caused by yeast from fermentation or bacteria. Not boil off. Are you thinking of DMS?

 

[day_trippr]

Whoops. That'll teach me to split attention 'tween ball game and posting.

You're right of course. Ignore that part

Cheers!

 

[Conehead]

How clean is your beer line? If you use a tap, is it clean? Gelatin will drop that yeast into a nice little pile on the bottom of your keg.

 

[rdkopp0153]

That's my thought too, that the beer line might be funked.

 

[biertourist]

Yep beer line infections can produce diacetyl. Clean those beer lines!



Also perform a "Diacetyl force test" with a large sample from the wine thief directly from the keg. -Put the sample into a small glass (feel free to let it oxygenate a bit) then heat it up to say 80F for 10 minutes, then chill it back down to drinking temp and taste carefully for the presence (taste and texture) of diacetyl.

You may have pulled the beer off of the yeast too soon and you may still have diacetyl precursors (VDK) in the beer - oxygen and time will convert that VDK into Diacetyl that you can taste -the reaction is sped up considerably at higher temps.

Note: You don't HAVE TO chill the beer back down before tasting but 80F beer is gross, so I'd still do it anyway. ;-)

-If your sample from the keg passes the "VDK Force Test" you know that neither the diacetyl nor the diacetyl precursors are in your keg and it's coming from somewhere downstream (lines / tap/ glycol chiller).


Adam