By Scott Stewart - Mar 15, 2022
McAllister Brewing Company (North Wales, PA) has created a new delicious farmhouse ale series called Never Nude!
Yeast harvesting for the Never Nude Series:
Years ago, I was introduced to the world of beer-making by the head brewer of McAllister’s Brewing, Michael McAllister. Up until that point, my palate was unrefined, and my only real knowledge of beer was how to drink it.
As the years progressed, and my interest in beer grew, I started to explore what makes a beer, beer. There are hops, grains, water, and the ingredient I found most interesting yeast. This single-cell fungus is the magic living organism which turns wort into beer. Where does the yeast come from, and can I find it myself were the questions that I kept asking. So, I did what any practical person would do when faced with a question they couldn’t answer themselves…I turned to YouTube. From there, my eyes were opened to all of the possible ways yeast could be harvested and used.
I started with a jar of wort placed in my garden with some cheesecloth over it. I left it out overnight on a windy spring day. The next day, I placed the wort into a sanitized Erlenmeyer flask with an airlock. After some time passed, I found that I had some CO2 production, and what looked like krausen. When I popped open the airlock, I smelled that noticeable fermentation odor, but also something else which was pretty unpleasant. Back to the drawing board. I then asked myself, how can I refine my yeast harvesting technique to get a purer strain? This once again led me back to YouTube.
After several hours of reading and watching videos, I realized that my current setup was far from what it needed to be in order to safely and effectively harvest yeast. If this blog was a movie, this would be the scene where inspirational music comes on and you see me hard at work building something in my basement. Several trips to Home Depot and a number of Amazon orders later, I had my yeast harvest lab setup. Let the fun begin.
Using my own recipe, I made several agar plates that also contained a small amount of light malt extract, more commonly known as DME. I also made several test tubes filled with low-gravity, 1.010, wort. Some of the test tubes were filled with vegetable flowers from my garden. Others contained cotton swabs which were placed into the test tube after the skin of the fruit was swabbed. It’s important to note, that before I placed the flowers into the test tubes, the local bees were given plenty of time to pollinate them. All the test tubes were then placed into an ideal yeast growing environment and bumped every so often. After three days the flowers and cotton swabs were removed, and all of the test tubes were moved into a refrigerator to sit for another three days. Then the flowers and cotton swabs were removed and the test tubes were prepped for streaking onto an agar plate.
Finally, the time had come to see what was growing inside the test tubes. Using an inoculating loop, an alcohol-burning lamp, and other protective equipment, I removed a small sample and streaked it onto an agar plate. All plates were properly labeled and set aside in a clean-air environment. After three days passed, I was finally able to see what was really inside the test tubes. I want to quickly pause here to give a big shout-out to Sui Generis Brewing and his YouTube page. Without his expertise in yeast harvesting and awesome instructional videos, I would not have had a clue what I was looking at on the agar plates.
Once I was able to see what was on the first agar plate from each test tube, it was time to refine the samples even more. Again, using an inoculating loop, an alcohol-burning lamp, and other protective equipment, I removed a small sample from each agar plate and streaked it onto a new agar plate. I then waited another three days, removed a small sample from the second agar plate, and streaked it onto a third plate. I then repeated that step one more time. I know it sounds like a lot, but getting the purest sample possible was the goal, so patience was required. Finally, I was left with the purest sample I could make without being in an actual laboratory. I then made some agar slants and transferred samples from the agar plates to the slants. Once the yeast on the slants had some time to grow, I added purified water. The water was filled to the top to remove all air, capped off, sealed shut, and refrigerated.
As I looked at what I had accomplished, I couldn’t help but ask myself, what kind of yeast was this? After all, there are hundreds of strains, all of which have their own defining characteristics. I once again turned to the internet to search for a company that would test my sample and tells me exactly what I have. After some time reviewing possible companies, I settled on WildPitchYeast.com. Matt Bochman and his team were great to work with. In a short time, they were able to take my sample, refine it further, and then tell me the exact yeast species it was. For a small fee, he also made a five-gallon pitch for me in his laboratory. With Matt’s help, I was finally able to bring to fruition the wild yeast I had harvested for the Never Nude Series.