The “Drie” strain(s)
As can be seen from reading through the blog, I have been repeatedly culturing what I thought was a single Brettanomyces strain acquired from the dregs of a bottle of Avery’s 15th Anniversary ale. The strain they used for the 100% Brettanomyces fermentation is referred to as “Drie“, as it was cultured from a Drie Fonteinen gueuze bottle by the Brewing-Science Institute. I have been re-culturing the cells from the Avery 15 bottle over and over again for the past 2 months yet have reported very little in the way of findings, just some photos here and there. What I have repeatedly observed and am finally confident enough (process repeated 4 times) to say is that the “Drie” strain has actually cultured up as two different and quite unique Brettanomyces strains. When looking at the photos listed below, there is a matted phenotype and a glossy phenotype on MYPG agar. On WLN agar the two strains form different shaped colonies and the colors are slightly different also. On CuSO4 agar the two colonies differ as the matted phenotype forms an intense brain like domed structure with a beige color while the glossy phenotype develops a volcano shaped beige colored round glossy colonies with an off-white center tip. Under the microscope there is also a slight difference in the cells, one which is noticeable. The matted phenotype cells are rugby ball shaped and slightly larger then the jelly bean, cylindrical, tiny glossy phenotype cells. Both strains are nearly half the size of the strains which White Labs offers. In the future I plan to do PCR to identify the the two species of Brettanomyces, but for now they are being propagated up separately with daily cells counts being taken to observe growth phases during batch culture propagation and then for use in pure culture fermentation.
I don’t know the exact reason why there is two morphologically different strains culturing up when only one was used to ferment the beer. My guess is that over time the original strain has mutated possibly due to environmental conditions and a second strain has become established. I might possibly be able to tell more after looking at fermentation characteristics, but for now the glossy phenotype is believed to be the “Drie” strain and the matted phenotype is a completely unique new strain.