About two months ago I began experimenting with harvesting wild yeast from different areas in my house. Since most of my beers are fermented in the basement where our Westland Distillery whiskey barrel resides (and because we inoculated it with commercial wild yeasts and bottle dregs after our clean stout was finished) I decided to try to catch some yeast from the basement. The process is rather simple, though unpredictable, and so far I’ve been successful with two separate batches — successful meaning I’ve definitely caught some bugs and there doesn’t appear to be any mold or off flavors present at this point.
After Gregory and I finished sparging for the chanterelle mushroom beer, we had about 64oz of wort left over. Instead of just dumping the wort, I let it cool to room temperature and put it into a stock pot which I covered with a grain bag and left in my basement over night. The next morning I funneled the wort into a gallon growler, added an airlock, and waited to see what happened. In about a week’s time, I noticed that a Brettanomyces pellicle had begun to form. I waited another week then made up a starter wort and fed the bugs I caught, taking the opportunity to smell the yeast: mango- and pineapple-like tropical fruit notes with some light barnyard funk is what emerged. I have been monitoring and feeding the batch roughly every two weeks ever since, cold crashing and decanting when necessary, and Gregory and I plan to use it in our turbid mash lambic-style ale which we plan to barrel ferment. It has been exciting to witness the different phases the yeast has gone through since it’s initial capture: a few weeks after the first feeding, it was offering more standard Belgian yeast notes; now it has become fairly complex with hints of fruit, a more profound funkiness, and light Belgian-like phenolics.
The second batch is from upstairs in my kitchen. After we finished sparging for our Baltic porter, we had about 32oz of wort left (prior to the addition of the cold steeped specialty malts which were added at the end of our boil) and I followed the same process as above, keeping it on top of a cabinet for the night. Once again I definitely caught some bugs, and it is my hope that this batch will be more representative of the wild yeast down here on Alki beach since I do not ferment any beers in my kitchen. So far this yeast seems milder in intensity with a light fruitiness reminiscent of stone fruit and a very faint funk in the background. It will be interesting to see how both of these catches mature and change over time.