Diacetyl Rest Didn't Clean Enough

[jinjosavior]

I'm working on my first 2 lagers right now. Pulled them from 50 F to room temp of 65 F at exactly 75% atten. Now, about 3 days later, they are at FG of 1.008 and 1.009 which is perfect for what I was expecting, but I still taste buttery flavors. What went wrong and what is there I can do to clean these beers up if anything?

Thanks!

 

[Yooper]

I'm working on my first 2 lagers right now. Pulled them from 50 F to room temp of 65 F at exactly 75% atten. Now, about 3 days later, they are at FG of 1.008 and 1.009 which is perfect for what I was expecting, but I still taste buttery flavors. What went wrong and what is there I can do to clean these beers up if anything?

Thanks!

Keep them at diacetyl rest temperatures, even raising the temp a tiny bit if needed, until the diacetyl is gone. It will get worse with lagering, not better!

 

[jinjosavior]

Will it continue to eat the diacetyl even after it reached FG?

 

[Yooper]

Will it continue to eat the diacetyl even after it reached FG?

Yes as long as the yeast are still active.

 

[jinjosavior]

The beer itself has cleared, but there is still a layer of clumps floating. Would a little rousing be a bad idea?

 

[Yooper]

The beer itself has cleared, but there is still a layer of clumps floating. Would a little rousing be a bad idea?

I probably wouldn't. The yeast should still be in suspension, at least the active ones, so rousing wouldn't give much of an advantage if any at all.

 

[insanim8er]

Yes as long as the yeast are still active.

I've read - I think palmer's book - that sometimes so much is produced, that the yeast can't clean it all up.

ya I found it:

"Diacetyl is most often described as a butter or butterscotch flavor. Smell an unpopped bag of butter flavor microwave popcorn for a good example. It is desired to a degree in many ales, but in some styles (mainly lagers) and circumstances it is unwanted and may even take on rancid overtones. Diacetyl can be the result of the normal fermentation process or the result of a bacterial infection. Diacetyl is produced early in the fermentation cycle by the yeast and is gradually reassimilated towards the end of the fermentation. A brew that experiences a long lag time due to weak yeast or insufficient aeration will produce a lot of diacetyl before the main fermentation begins. In this case there is often more diacetyl than the yeast can consume at the end of fermentation and it can dominate the flavor of the beer." - http://www.howtobrew.com/section4/chapter21-2.html

 

[Yooper]

Yes, that's true. Underpitching, especially a bit too warm, with a notorious diacetyl producing yeast strain may have that problem. But this beer may still clean up at room temperature a bit and that's worth a try.

 

[BigFloyd]

Yes, that's true. Underpitching, especially a bit too warm, with a notorious diacetyl producing yeast strain may have that problem. But this beer may still clean up at room temperature a bit and that's worth a try.

This is why it's much better for lagers to pitch plenty of yeast, 1.50 pitch rate at least, into cool (45*F) well-oxygenated wort.

+1 on leaving the d-rest go on. A whole week wouldn't hurt. The time to deal with it is now.