I have been brewing for around 15 years, off and on. While I've had bad batches, this is a first: I brewed up two batches of beer, extract with specialty grains, on Saturday at a friend's house. I left my yeast there, and didn't pitch until Sunday around 11 am. I pried the top off of one bucket and low and behold there was a quarter inch of krausen on the top of the beer into which I was planning on pitching my yeast. At a loss of what to do, and with an opened vile of yeast in my hand, I pitched anyway and hoped for the best.
Now, something, of course, got in there, but what? I washed and scrubbed the bucket with soap and water, then used two different acid based sanitizers from the homebrew store, washed the bucket out with tap water then rinsed with spring water (crappy tap water in southern cali has soured more than a few of my beers) and sealed the bucket with air lock in place. After brewing, I poured the boiling hot wort into the bucket, topped it off with more spring water then sealed the bucket, took it home and placed it in a larger tub filled with water to keep it cool. The air lock was farting away the next day when I went to pitch, so I cannot imagine the bucket lid being ajar, and even if it was, what random, wild yeast strain could have been powerful enough to create a krausen in less than 24 hours?
I am still at a loss as to how this happened.
Any words of wisdom (besides throw the damn bucket away, which I'll probably end up doing) would be appreciated.