I was checking on the wheat beer that I split and racked onto persimmons and black raspberries, and I noticed that there was some foam on top of a third fermentation vessel in the same closet. In that vessel, I had left a little wheat beer and slurry, onto which I poured a diluted black raspberry juice syrup. The first dilution was probably not thin enough, because the yeast did practically nothing, but when I diluted it further, the yeast still refused to act.
So I did what the lazy man does: I left the quart jar of twice-diluted syrup in the closet to deal with later, and/or to see what might happen. Today, I found it bubbling away, with the bubbles rising to the top, apparently out of the yeast cake. This is odd behaviour, since the yeast is top-fermenting, but perhaps the syrup-water-beer solution is still too thick and viscous to allow the yeast to float up in any great quantity. I’m not sure, but it is clear that significant fermentation activity is going on.
I tasted a small sample, and it’s still very sweet. I couldn’t taste any alcohol in it, but Miss Jiwaku (who has a much stronger sense of smell) says she can smell alcohol in the sample. Right now, I’m torn about whether to dilute it further and see whether the fermentation picks up, or just leave it and see how it goes. I’m tending towards leaving it alone, though, until this activity subsides, and then diluting it to the kind of thickness I prefer, and/or perhaps adding some yeast with a higher alcohol tolerance to the remainder to see what it ferments into.
I still have some of the original syrup bottle, and could probably adjust the thickness of the solution if I over-dilute it. Perhaps I shall try it in my little 3-liter fermentation jug. I think I’ll make up my mind tomorrow.
And, slated for tomorrow (er, Friday, that is): a bunch of grading, and… I think I’m going to brew up some more beer. Likely a second attempt at my On a Jag Abbey Dubbel, using this recipe.