Okay, this has reached the point of weirdness. My Coffee Stout is still fermenting.
Or, rather, once again it has begun fermenting energetically, which is, I think, a fair bit weirder than “still.”
I started this one beer on the 17th of November, which puts us at just over two weeks. That in itself isn’t quite so weird, but consider this: it pretty much stopped fermenting after about five days or so. I racked it to a carboy for secondary fermentation. There it stayed until it reached about 1.010, which was the gravity the last time I checked it. I thought it was a case of stuck fermentation, so I started some more yeast, with some brown sugar — not a ton, but more than just a little bit — and added it.
Suddenly fermentation began again, and died down. When it seemed like it was al over, I dry-hopped the beer. But then I noticed that a fair amount of trub (dead yeast and other gunk) had accumulated at the bottom of the carboy, so once the fermentation died down again, I racked the stout to a new carboy. (With the added hope of eliminating some of the hop-gunk, since I realized I’d added some strong hops and didn’t want to overwhelm the coffee flavor.) Sure enough, the very next day, very vigorous fermentation recommenced! Like, almost as vigorous as at the start of the fermentation — vigorous enough even for the top of the airlock to be sticky after the first night. There’s a rich foam and a constant flow of bubbles to the surface even now.
The only things I can think have happened are that:
- I did put in a fair bit of malt extract for this one, so there was still some sugar in there waiting to be fermented, even though it didn’t taste all that sweet when I first tried it.
- The sugar I added was sucrose — and brown sugar, at that, meaning more impurities and so on — which is harder for the yeast to ferment. So it’s going more slowly, and maybe it was well-distributed when I pitched that yeast starter back in the time of the first rack to carboy.
- Maybe some particulate matter — mainly coffee grounds from the original wort — were interfering with fermentation finally were eliminated during the last racking process, and now the wort is fermenting naturally?
- I used a trick with my double-pipe carboy cap, sucking a little air out of the carboy to create a vacuum which got the siphoning going. I had to restart it a couple of times, which may have aerated the wort somewhat… and maybe helped wake up some yeast that had gone prematurely dormant.
It’s quite possible something more sinister has happened, but I don’t think so. There are no weird odors, and the beer seemed to have a fair amount of alcohol last time I tried it, so I’m not concerned about bacterial infection. But I am curious to see what’s behind this.
For now, I’ve introduced a heating pad on a low setting into the closet where the beer is fermenting, just to see if warming up the space helps speed things up a little bit. I do suspect this is a good thing, whatever is happening, but it still has me curious!
UPDATE: No, not about the beer. But, muhahaha, I’ve been reading up on the making of apple cider, and despite the cost of apple juice in Korea being significantly higher than in some places I’ve lived, I still have a hankering for it. The case of almost-2L apple juice bottles I ordered just came in, and now I just need to get some bottles that can handle the pressure of carbonation. Now all I need is some sugar, and I’ll be set to brew up a batch of apple cider (for you North Americans, that’s “hard cider”) this Friday, probably to be bottled next Thursday, so they’re ready to drink just over a week later. Whee!
And yeah, it’d be more fun if it were fresh apples, I agree, but that ain’t gonna happen till the fall. No biggie. However, I may follow the instructions here and make candi sugar for use with the cider… it’d be nice to get a little more alcohol, a little less body, and a little faster ferment. This is one I want to ferment in the plastic bucket with a valve, so I can taste it regularly as I go along. I think I’ll start with about 6 or 8 L and see how it turns out. If it comes out well, I’ll be able to make another batch quite easily. It doesn’t take too long to make, and on the other hand if it turns out badly, I won’t have wasted a bunch of juice on a bad batch.