For the second time in my homebrewing career of many years, I have a snake in my boots. I mean, there are some critters getting into my beer that I didn’t invite to the party! Recently, I’ve had 2 beers accidentally start to sour and/or form a pellicle on the surface (a bio-film usually formed by lactic acid bacteria).

This is not the end of the world. The first was my Belgian peach ale, which I’m just aging now to see how it evolves over many months. I’ll probably use some oak eventually and possibly more peaches and/or a tad of lactic acid, since the IBUs may be a bit high to really get much lactic acid produced (if you are making a sour by traditional methods, keep your IBUs below 5!).  Sometimes accidental sours can be amazing. Crystal Springs Brewing Company last Spring had a dark beer aging in barrels that soured unintentionally and the beer was absolutely amazing.

My fresh hop beer gained a funky fruitiness that actually went well with the beer and was not present in the other half of the batch that my brew partner took home and fermented on his own. It was noticeably more tart than his clean half as well, and the pH was about 0.4 points lower when we tested with a pH meter.

I’m lucky to live in a town with such an awesome brewing community. I was talking to Bryan Selders, formerly head brewer at Dogfish Head and currently brewmaster of The Post Brewing Company about this and he said, “bring by a sample, I’ll plate it and see what you have”. So I did and here’s the scoop: Acetobacter – no surprise here, the fresh hop beer as it warmed had a noticeable vinegary flavor in the background. But Bryan also found a very vigorous wild yeast strain. This was very unexpected since the media on the plates he used is yeast inhibitory and intended to isolate bacteriums instead. It’s very easy to tell the two apart with a scope, so no doubt it was yeast. This wild isolate grew incredibly well in an aerobic culture and less so in anaerobic. Well, there you go. Homebrew long enough, especially if you make intentional sour and funky beers as I do, and you’ll get a snake in your boots too eventually! This is one of the good things about kegging – you don’t have to worry about bottle bombs due to contamination over-carbonation. One final word, no pathogens can live in even low abv beer, so you are always safe to drink your homebrew no matter how contaminated it is. Yay!