Diacetyl

I brewed a 10 gallon batch of BM’s Centennial for an upcoming Christmas party. I’ve brewed it in the past for a graduation party and it was well received by the masses. My recent batch was split into two 5-gallon fermentors; one a plastic bucket and one a glass carboy. I tossed a packet of Nottingham into each. Fermented at 63* for 9 days then each was racked into a secondary with gelatin. Odd thing, the beer in glass carboy has that butterscotch flavor that I associate with diacetyl. The other batch does not. I’m gonna krausen the offending batch to see if it clears it up.

With this batch I did some things I usually don’t do:
I usually don’t move the beer off the yeast for minimum of 2 weeks (longer depending on the gravity), but I wanted it ready for the party and I was going to do the following
secondary - which I usually don’t do
use gelatin- which I usually don’t do

In hindsight the off flavor was there when I racked it to the secondary, but in my haste I ignored it. Had I been patient I could have taken care of this while it was still on the yeast, but …

As I said, the second batch is free of butterscotch so there may still be time to save Christmas.

was the bucket or carboy first?

Perhaps the bucket received more yeast during transfer and its worked it magic.

I have an Amber Lager that has the butter taste pretty bad. It somehow got the diacetyl in the keg, I did not notice it when I kegged the batch. I mixed up a starter with some US-05 and have it churning now in the keg now.

BargainFittings said:

was the bucket or carboy first?

Perhaps the bucket received more yeast during transfer and its worked it magic.

Click to expand...

That's exactly what I was thinking. The yeast should clean it up eventually.

There are diacetyl producing bacteria. I would definitely suspect infection in the case where there was no diacetyl detectable at kegging and it shows up later (Cpt Kirks) and I think it is also perhaps the best explanation for what the OP experienced (same yeast, same temp, same fermentation time, same pitching rate, same wort but diacetyl in one sample but not the other)

Warm that fermenter up to 67+ for a few days.

Here's another discussion on diacetyl.

Christmas was indeed saved ... at least the party was. I had the Blonde, a Brown Ale and an IPA on tap. Along with some bottled porter and a stash of RIS. The blonde Ale kicked first - then the Brown. The IPA (my favorite) still has a few pours left hopefully it’ll get me through Christmas. Many of the guest were surprised that the beer was so good.

Thanks BierMuncher, people really enjoy the beer (when brewed and fermented properly).

I transferred the Blonde back into a carboy (I needed the keg) and warmed it up, but haven’t done anything else. I’ll give it a taste later this week. I’m not sure if enough viable yeast is left to do the work, so I might have to add some active yeasties.

Why one batch and not the other? The batch with the butterscotch flavor was in the carboy. Both batches received the same amount of yeast, one packet each.

I puzzled about this ... I puzzled and puzzled until my puzzler was sore, then I thought of something I hadn’t before, Perhaps, it’s oxygen - maybe my yeast needs a little bit more. Currently I aerate by sloshing around the runnings as I siphon the kettle. It’s a bit easier to do into the wide mouth of the bucket. I’ve been good this year so I hope Santa brings me my oxygenation system.

Really interesting, I noted in Soperbrew's last batch of this exact same beer a wee bit of diacetyl I never noticed before in any of his or my brews. Strange to read you had a similar experience with the same yeast, no less. There wasn't much but I'm pretty sensitive to it so I picked up on it right away.

Perhaps the common thread here is moving to secondary using the Nottingham yeast without giving it a adequate D-rest above 67*F. I don't have a lot of experience with this yeast so I'll be sure to do that the next time I use it.