Capturing Our Own Local, Wild Yeast
One of our biggest goals is to brew a great, all North Carolina beer.
We’re really fortunate to have a number of local farms growing hops, and if you’ve followed our Instagram, Facebook, or Twitter you may have seen that we had some success with our own Cascade plants. We also have a pretty fantastic local malt house just up the road: Riverbend Malt House. But what about the yeast?
We asked ourselves the same question, and decided to capture our own local yeast from our backyard.
It turns out, that yeast harvesting takes a pretty steep learning curve, and I’m sure that our method is a long shot from being ideal. However, through a lot of trial and error and many generations of yeast, we have a strain to call our own, and it makes really great, kind of funky beer. The rest of this post is how we did it.
First of all, there is yeast everywhere. It is on pretty much every piece of fruit and if you just leave unfermented beer (wort) outside for a few days, it will begin fermenting. The problem is that more often than not, this makes really awful beer. There is just too much out there that is bad for flavor. I had read, however, that leaving beer in an orchard often leads to good beer. This inspired us.
To find a yeast that makes good beer, we began with our blueberry bushes. I picked a handful of ripe berries and even took some that had fallen off the bush, and then in the spirit of science, dropped them right into a yeast starter (boiled down malt extract and yeast nutrient). Then I left it on my desk for about two weeks.
Each day there was a new development, and I pretty much watched a little civilization begin. First, the bacteria took over. A thick pellicle formed, and at this point, it seemed like this was a very bad idea, but about 10 days in, the telltale signs of fermentation began. Small bubbles began rising to the surface, and I was pretty sure we had some yeast. Excitement!
Round 2 consisted of isolating the yeast from the pellicle with the goal of removing some of the bad-for-beer organisms. Then I re-pitched the good-for-beer organisms into a fresh starter. The difference this time was that I dropped the pH way down to prevent bacteria from taking over.
Round 3 was pretty spectacular. This starter took off like a rocket, and we were feeling pretty good at this point. There was definitely yeast at work, and when we smelled the starter, it smelled pretty good. Now we had to isolate a single colony of yeast from what was a whole variety of microorganisms. This meant plating the sample onto agar plates.
To keep this short, basically what you do is make up some malt extract/ agar plates and streak a sample of yeast across it. When you find a circular, clean colony spring up, you scoop it off and re-pitch it into its own starter. The idea is to culture a colony of only a single yeast.
We had a lot of mixed results and had to re-plate and re-culture a bunch of times, but finally, we landed upon a yeast that attenuates well, smells and tastes great, albeit a little sour, and is from right out of our backyard. Success! We call it Rabbiteye in tribute to its beginnings on our Rabbiteye Blueberry bushes.
When we finally open our doors in 2014, we will definitely brew our all NC beer, but we will keep it to small batches. Our yeast is a strain of Brettanomyces, and if you let “Brett” into your brewery, it can be very, very hard to get it out. This beer will be brewed as a pilot batch and fermented in an isolated area, but maybe that makes it even more special!