Diacetyl from Bottle Fermentation?

Is it possible to not have diacetyl problems at bottling, but the bottle fermentation causes it after the fact? I think this might have happened to me...or maybe it's just something else. Thoughts?

It shouldn't be an issue if you let the main fermentation run its course and clean things up. The bottling fermentation is really very minor.

Yeah...everything was perfect at bottling when I tested/tasted the still beer. One of the best I've done, IMHO. But now, two weeks into bottle conditioning, it tastes different. Much different. My friend thought it might be diacetyl, but I've never heard of diacetyl from bottle fermentation.

Maybe it's just the fact that it's still "green". I've just never had a beer change this much between the bottling bucket and the glass.

Which beer is it?

London Ale. My attempt at an ESB, but I don't think my efficiency was where it needed to be, so it ended up being, at the best, a regular ol' bitter. But gawdAMN it was the best beer before I bottled it. Hopefully it'll get back to that.

On a related note...I had to say goodbye to my Wyeast London ESB yeast after its second use. I harvested it from the London Ale and pitched onto my cherry stout. Well, with all those cherries in the fermenter, it mucked up the trub something awful. It just wasn't worth saving. On a better note, though, I used it twice, so I cut my cost in half...yea!

Evan! said:

Yeah...everything was perfect at bottling when I tested/tasted the still beer. One of the best I've done, IMHO. But now, two weeks into bottle conditioning, it tastes different. Much different. My friend thought it might be diacetyl, but I've never heard of diacetyl from bottle fermentation.

Maybe it's just the fact that it's still "green". I've just never had a beer change this much between the bottling bucket and the glass.

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2 weeks? Not long enough. Where are your bottles conditioning? Nice cool closet somewhere? Or in the fridge?

Priming for bottling is causing a "mini" fermentation, so the flavors will change until it finishes. Where your bottles are stashed while this happens will make a big difference on how long it takes.

But I doubt 2 weeks is long enough at any rate. As long as you didn't do anything bad between secondary (when you tasted it and said it was ok) and bottling, I doubt anything bad has happened.

How many did you sample? Perhaps it was one dirty bottle?