When I got home yesterday, the mysterious krausen had already dropped and the beer was bright again. There's not much sediment in the bead sample jar (especially compared to the control sample), so if renegade yeast broke free from their containment and attempted to repopulate, it was a short-lived rebellion.
I know it's still early, but I couldn't resist the temptation to pull a few samples to taste. I took a bit of each beer and crashed them in the fridge for ~24 hours. They've both reached equivalent (presumably terminal) gravities and they are identical in color. I had my lady friend pour a triangle test and I let them warm up to the low 50s. I don't have a great palate, but the difference was very significant. Here are my notes:
Beer B, C
: still quite green, significant acetaldehyde; very "British", with fruit tones (apples, grapes) and sweetness. Muddled and harsh hop bitterness.
: Very, very clean. Not quite bland, but rather thin mouthfeel. Hops punch through, stay neutral. Grain.
As I later discovered, B&C were the control and A was the bead-beer. At this point, I don't think there's much of a conclusion to draw, since the control beer still tastes so young. For example, I don't know if it's the bead-beer that's thin or if it's just the recipe's thin and the control beer doesn't come across that way yet.
What's most striking, though, is that the bead beer tastes like a *finished* beer even though it's just five days old. It's not a great
beer, but nor is it a terrible one. Then again, this wasn't a recipe for a great beer. I'm pleasantly surprised, at least to the point where I intend to keep experimenting.