Fermention "Restarted"

A few weeks ago I brewed an all grain black IPA. OG was 1.062 and after 2 weeks in the primary the gravity was 1.012 on consecutive days. I racked it to my secondary and added my dry hops. My wife and I were traveling for the holidays, got snowed in, etc. Fast forward 3 weeks... I was planning on bottling today and I opened my fermentation chamber only to see bubbles on the top of my beer and the airlock bubbling. Strange right??? I wouldn't really call it a "stuck fermentation" because it had already attenuated fairly well (or so I thought). I guess I'll just wait until visible signs of fermentation stop and I'll start taking gravity readings again. I'm not worried, I'm just curious if anyone else has had this happen and what caused it to start fermenting again.

Bubbling could just mean that the temp or pressure changed. It happens all the time.

Here is a good video showing that bubbling really does not mean anything.

The bubbles on top of the beer make me wonder. Maybe just kraeusen that never dropped back down. I hope you'll let us know how it turns out.

It's not just the airlock bubbling, there is nearly a solid layer of bubbles across the top of the beer. There is definitely fermentation activity going on, I just don't know why it started so late. The temp is a steady 60-62F. I use a temp controlled chest freezer for a fermentation vessel. I know that sometimes when you transfer to a secondary it can rouse the yeast, but it has been in the secondary for nearly 3 weeks.

WoolyBooger said:

It's not just the airlock bubbling, there is nearly a solid layer of bubbles across the top of the beer. There is definitely fermentation activity going on, I just don't know why it started so late. The temp is a steady 60-62F. I use a temp controlled chest freezer for a fermentation vessel. I know that sometimes when you transfer to a secondary it can rouse the yeast, but it has been in the secondary for nearly 3 weeks.

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Take another reading. If its dropped further it may not have been done or you may have an infection that's started consuming the rest of the sugars that did not ferment previously.

I've been thinking about this all day and it's been driving me nuts. So I looked back at my numbers in beersmith and my last readings were steady at 1.020 not 1.012 as I stated in my previous post. I was looking at another version of the same recipe that i had previously brewed. The current reading is 1.013. That makes a little more sense, but still doesn't explain the stuck fermentation. I used a starter, so the yeast shouldn't have been stressed and I shook the bejesus out of the carboy to aerate as I always do. Any ideas?

Sometimes the yeast just take a while to snag those last few points.maybe the temp changed or the pressure or whatever but it obviously kept working.

If the beer looks and tastes fine then take another reading in a few days and see where it's at.

duboman said:

Sometimes the yeast just take a while to snag those last few points.maybe the temp changed or the pressure or whatever but it obviously kept working.

If the beer looks and tastes fine then take another reading in a few days and see where it's at.

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I tasted my hydrometer sample and tastes about like it should. I will continue to take readings. I'm sure it will turn out fine. I just want to know what caused the stuck fermentation so that I can avoid it in the future.

I'm not sure it stuck...It may have just really slowed down and not stopped. If you are using extract there can be a wide variance in it's fermentation behavior...I think it just needed the extra time. Beers in that OG range can take several weeks to ferment out.

helibrewer said:

I'm not sure it stuck...It may have just really slowed down and not stopped. If you are using extract there can be a wide variance in it's fermentation behavior...I think it just needed the extra time. Beers in that OG range can take several weeks to ferment out.

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It was an all grain brew with no added extract. I used S-05 and made a starter. This is the same yeast/process I have used 2 other times for this recipe and it usually ferments out in a week or so. I know that 2 prior successful brews doesn't mean my process is flawless or anything, but I followed the same procedure as always. Maybe my yeast just wasn't up to par for some reason.