Will Lagering Clean up Diacetyl Completely?

[Morkin]

Brewed a Premium American Lager about 5 weeks ago. I fermented for about a week and a half, and at the end of the fermentation (yes I checked with hydrometer) I did a Diacetyl rest for 2 days at around 65. I fermented at 55.

When I transfered to secondary, there was no hint of Diacetyl. It's been lagering at roughly 40 degrees, or as low as my fridge will go, for about 3 weeks now. I was going to bottle at around 4 weeks, but I had a little taste last night and it had an overpowering butter smell, and a fairly heavy butter taste.

It's May 20th, and I want these beers ready for my wedding on July 24th for my Groomsmen. Would it be best to just let it Lager for another 2 months and see if it gets better? Would Lagering it longer take away the Diacetyl? I did the rest, so I"m not sure why the flavor is there. Temp control, good fermentation, everthing was supposedly done right. SG 1.048 FG 1.010-Roughly. Any thoughts?

 

[big supper]

Seems weird that you would have diacetyl appear later on. Some bacterial infections can cause diacetyl. I am not sure that lagering longer will help the problem as it is the yeast that usually take care of the problem and that is at a higher temp as you know. I am no expert when it comes to lagers though.

 

[Morkin]

Mouthfeel, Color, and Body all seem to be about right and there are no signs on an infection. I thought I had read where Lagering can make Diactly go away after awhile...

 

[Yooper]

I wonder why the diacetyl shows up now? Unless it was present before, but the lagering makes it seem more present?

A little diacetyl manifests as a "slickness" or oiliness on the tongue. A lot of diacetyl gives butter or butterscotch flavor. The problem is that once the beer is off of the yeast cake, there aren't a ton of yeast to clean up the diacetyl. It probably won't get better while lagering, since the yeast are pretty dormant at cold temperatures. I guess I'd try warming it up and seeing if the yeast can take care of the diacetyl.

I don't think repitching will help much, but I know that some other homebrewers have done that with good results. That could be a possible solution to try.

 

[jacksonbrown]

Lagering will not help at this point. Make a small, 1-2 liter, starer of lager yeast, any will do, and pitch it when it's active. Let it ferment out at 50-55 for a couple weeks, even a month. Then give it a few days at warmer temps. This probably won't eliminate the diacetyl completely, but it will help to minimize it.
I think your first problem was not letting it ferment long enough. You really need to give a lager more time than 10 days. 3-4 weeks is more ideal, then a few days of diacetyl rest, then lager for like 6 weeks.
A friend of mine who is strictly a lager brewer told me that he ferments at 45 for 4+ weeks to avoid diacetyl all together, thus negating the need for a rest. I'm going to try that method in a few weeks (brewing my starter this weekend).

 

[Yooper]

A friend of mine who is strictly a lager brewer told me that he ferments at 45 for 4+ weeks to avoid diacetyl all together, thus negating the need for a rest. I'm going to try that method in a few weeks (brewing my starter this weekend).

Actually, I have the same experience. If you pitch a BIG starter at fermentation temperature (I've never gone as low as 45 degrees, but will go to the yeast strain's lowest recommended temp by the manufacturer), and allow it to ferment out at those cool temperatures, a diacetyl rest isn't always needed. I've only actually had perceptible diacetyl in one lager after primary. It wasn't buttery, but there was a "slickness" in the mouthfeel. It went away after a diacetyl rest.

of course, some yeast strains produce more diacetyl than others, so for a notorious diacetyl producer, maybe a diacetyl rest as a matter of course is a good idea. I think pitching warm and then chilling also requires a diacetyl rest.

 

[Morkin]

I Used WLP840 American Lager Yeast, which is supposed to produce very little Diactyl.....

Is there any way I'm just delusional and that it will taste different when carbonated and it sits in the bottles?

 

[AnonyBrew]

If it were me, I'd probably try to warm it back up to 60F for a few more days to see if the yeast will clean it up, then step the temp. back down to lagering.

 

[menschmaschine]

Two things can cause diacetyl after fermentation: infection or oxidation (splashing during transfer). You can try krausening like others have suggested. It may or may not work, but it's about all you can do at this point.