Sour Dubbel

Hi Everyone,

I've done a lot of searching around the forum, but I'm not sure I've found the answer to my specific question.

I brewed a my second batch, a 2.5 gallon Belgian dubbel (followed a recipe from a LHBS), on 11/19. Used Wyeast 3787 Trappist High Gravity, and all seemed to be going well. After about 2.5 weeks in the primary at 68-72 degrees I noticed some strange bubbles/spots on the top. I decided to take a gravity reading and it had gone from 1.061 to 1.013, which seemed pretty normal. When I opened it up there was a pretty bad smell coming out of the fermenter (the bubbles looked fairly normal when looking into the carboy though, so I assumed I was just being paranoid). When I tasted the sample it tasted normal. You could even taste a bit of dubbel in the background.

Two days later, I take another gravity reading and it's 1.012. Not as strong of a smell this time. I taste the sample and it's now got a distinct sour taste that wasn't present two days prior. This didn't seem good, and since I wouldn't have a chance to bottle for another three days, I decided to bottle it today.

So, a few questions:

1) Assuming this is an infection, will the taste it clear up in time?

2) Assuming it's not an infection, could there be any other reasons for this?

3) For future reference, in this situation is it better to bottle or leave in the primary?

Thanks,
John

(1) Assuming you actually have an infection: no, the taste will only get worse.

(2) Yes, many. It sounds like active fermentation is coming to an end, and the yeast are beginning to be stressed. They'll create some off flavors briefly, and then start consuming those bad compounds during conditioning. So over time they should clear up. Incidentally, I don't think it is an infection; ordinarily, an infection will consume a lot of the sugars that yeast won't, so your SG will fall rapidly, essentially to 1.000. If yours only fell from 1.013 to 1.012, then I think you probably don't have an infection.

(3) I keep a set of liter bottles on-hand for batches I have concerns about. (Infection, recipe, temperature, whatever.) It means that I don't have to spend as much effort on bottling, which is nice. On the other hand, I've often been pleasantly surprised with how they turned out, so I'm glad I didn't chuck the beer. In your case, I'd leave the beer in primary for another week or two, and then bottle into your largest containers.

Thanks for the reply, I appreciate it.

That's potentially good news then. Maybe it was just some odd off flavors and it'll clean up a bit with time in the bottles. It was in the primary for 19 days (I'd planned on 21) so hopefully that's sufficient.

I did have a bunch of bombers on hand, so it's mostly bottled in those, plus a few small Duvel bottles that I'll try in 3-4 weeks.

Thanks again

Dang I was thinking mmm Sour Dubbel that sounds yummy?

Just an update. The dubbel has been bottled for just 8 days, but curiosity got the best of me tonight and I grabbed one of the small bottles. Surprisingly, it's not terrible. Of course with only 8 days in the bottle, it's still a bit green and alcohol-y, but the sour taste is probably 90% gone. So I'm optimistic that this will get better given time. So it seems that we'll chalk another one up to "it's probably not an infection", "don't dump your beer" and RDWHAHB.