Krausening to remove diacetyl

[motobrewer]

Well, I have 10 gallons of a 1.049 Helles that has just a touch too much diacety. I blame a weak fermentation due to an underpitch (WLP860). It's been lagering for 5 weeks and it's definitely gotten better over time. However it's still at the level where I feel it needs to be corrected.

So I decided to krausen the beer. I BIAB'd 1/2 gallon of beer using a scaled down version of the recipe and pitched some of the saved yeast from the main batch. After about 12 hours and visible krausen I pitched (as much as I could - they're in secondaries and were pretty full) at 63F.

Has anyone had experience with this? How long do I leave it at 63F? Should I lager it again?

 

[mchrispen]

I have krausened a few times... not sure it works like you think - seems to clean up sulfur more quickly and accelerate maturation for me, not sure it accelerates the clean up of diacetyl, but it might. Usually my lagers process D-Rest at 56F/58F for 3 days, then a very slow crash to 32F/29F, no more than 5 degrees a day - the slower drop seems to slowly put the yeast into rest without creating more esters. Maybe with a healthy krausen, you might shorten the D-rest by 1 day or so... depending on the amount created by your stressed primary.

Taste your beer twice a day with a very small sample - it seems to drop quickly over a short time - it can be hard to detect behind the sulfur. Mine get 2-3 weeks lagering, tasting at the end of week 2 for the drop of the sulfury yeasty flavors - I believe is called jungbuket. AJ has a ton more experience than I.

 

[brettwasbtd]

Could just be the yeast strain. Last lager I made with wlp800 was a butter bomb until 5-6 weeks of lagering in the keg, then it disappeared.

I would bring up higher than 63 now though, get that yeast working

 

[motobrewer]

I have krausened a few times... not sure it works like you think - seems to clean up sulfur more quickly and accelerate maturation for me, not sure it accelerates the clean up of diacetyl, but it might. Usually my lagers process D-Rest at 56F/58F for 3 days, then a very slow crash to 32F/29F, no more than 5 degrees a day - the slower drop seems to slowly put the yeast into rest without creating more esters. Maybe with a healthy krausen, you might shorten the D-rest by 1 day or so... depending on the amount created by your stressed primary.

yes, I employed a d-rest when it was about 1.008 points above terminal, as discovered by a FFT.

Diacetyl did get reduced during lagering period but in a diacetyl force test I notice small amounts in both the chilled and heated samples. It's not a large amount and it's definitely better than it was but it's still there.

I'll leave the fermentors at 63F as it's still fermenting the krausen wort until activity slows then re-lager it for maybe a week and see what happens.

 

[botigol]

I went through this earlier this year with my helles. The answer that I will give is leave it at an elevated temperature until it is done; no timeframe is appropriate for all situations. Gently stirring to keep the yeast in suspension isn't a bad idea either. Once you no longer detect diacetyl, then lager again.

 

[motobrewer]

Well, I added some krausen beer.

let it ferment, kept it at 60 for a few weeks. it changed nothing.

sadly, 10 gallons will be dumped.

 

[SpeedYellow]

Sorry to hear. I've had major diacetyl problems in lagers twice; both were solvable. In both instances, the beer was fine for a couple weeks in the keg, then became undrinkable d-bombs. Both times I fixed the problem by setting the kegs on their side in a warm area (72F), shaking occasionally. First time was with no added yeast; second time I pitched a rehydrated packet of yeast.

Both instances, I believe, were due to insufficient d-rests of 2-3 days. I target 5-6 days, but patience is hard!