It has been a while since I last posted about my Wild Yeast Project and for good reason. To refresh everyone’s memory, I embarked on a project to isolate either wild yeast or bacteria from a commercial bottle of wild ale, culture it in my lab, and characterize it for a batch of homebrew. My previous efforts involved culturing microorganisms from an old bottle of Cantillon Lou Pepe from 2004. Unfortunately, this experiment did not go well. All of the colonies that I did isolate were coliform bacteria and not what I was particularly looking for – wild yeast. It turns out that the bacteria grew much faster and outcompeted any wild yeast on the plate.
After many months, and finally having the time to come back to the project, I tried again from another commercial bottle of beer. Again I went to a potentially good source of wild yeast and obtained a bottle of Cantillon Blåbaer (2010 vintage). This is a lambic beer and one of their more famous beers. Aged on blueberries from Denmark, Blabåer is a collaboration between a Danish bottle shop, Ølbutikken, and Cantillon. It’s sold only once a year at this shop in Copenhagen and the limit is usually two per person. It is not distributed here in the states and I had the fortunate opportunity to trade for the beer on Beer Advocate.
I opened the bottle almost two months ago, but saved the dregs (about 50 mls) in a sterile conical tube and stored it at 4°C. The first couple of experiments that I did were complete failures:
- 20 μls of lambic slurry into 180 μls of sterile double distlled water (1:10 dilution).
- Made a serial dilution all the way out to 1:1,000,000.
- Plated 50 μls each onto a MYPG, MYPG + bromocresol green, and a WLD plate.
- Incubated at 30°C for two weeks.
- No growth.
OK, not a problem. I must have plated a sample that was too diluted. The next time I plated straight slurry to see if anything would grow. Nothing. For two weeks. At this point I was pretty concerned but confused. I could clearly see wild yeast and bacteria in the dregs with the lab microscope and they looked similar to the Lou Pepe samples. However, there was no growth on agar plates. As a last ditch effort I decided to inoculate 3 mls of wort that was filter sterilized (completely removes any bacteria) with 20 μls of straight lambic slurry. After four days of shaking at 37°C I got this:
In the 15 ml conical is what grew from the slurry after four days. I will post photos soon, but examining the yeast under a microscope revealed a wild strain that looked alot like Brett (small elongated cells). Also, the small fermentation in the tube was not from Saccharomyces cerevisiae as it smelled like sweaty gym socks dipped in vinegar! Another interesting thing to note was the yeast looked homogenous, as in they all looked the same. I wonder if I have one dominant strain?