After posting the first pictures of the bugs from the BFM’s La Torpille, I am still interested if some of the bugs there are Brettanomyces or not. I now took a sample of the bottom of the fermenter. There should be more cells than in the first post where I used a sample from the supernatant (= beer over the dregs). To make it easier for identification, I chose a more scientific approach and used my Neubauer’s counting chamber to have an idea about the size of the cells. So the width of the small squares in the pictures equals 50 µm.
Lets get right into the pictures:
There are some round yeast cells about 15 µm in diameter (little bit bigger than expected), and some longish cells with a length of about 20 µm (Fig. 1).
Another picture showing round smaller cells and longish cells. The longish cells in the middle seems to adhere together.
Figure 3 shows an overview of the different cells in the dregs
The last two pictures show similar cell structures (longish) as the other pictures before. The pictures are very similar to those from the first post.
All the pictures above were made with my microscope camera. I now tried to make some pictures with my smart phone and here they are in color. It seems that my smart phone has a microscope camera implemented…
It can be observed that the ends of the longish cells are not round. The cells seem to get wider at the ends. There is something else that gets me thinking. I could see yeast cells everywhere. They have a round morphology and a diameter of about 10 µm. The yeast cells should be the four round cells with a black ring around in the upper right corner of figure 7. But there are other cells which look somewhat different. They are smaller than the yeast cells. The size of these cells is around 5 µm. And they have a lemon-shaped form. And they are certainly not Lactobacillus (</= 1 µm) due to the size and morphology and not Pediococcus (< 1 µm). Maybe some other wild yeast strain(s) other maybe some form of Brettanomyces?
I will post these pictures in some homebrewer forums to get some feedback about the pictures. Maybe there is someone out there who could help me.
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Russ thought this beer tasted a little tart, hope you’re able to figure this out! We’re sure interested.
This beer is tart for sure. However depends on the age of the beer. Fresh samples are not as tart as matured bottles. In my experience, nearly every beer I tasted from BFM is somewhat tart or at least funky. Some say the brewery is infected by something (maybe Brettanomyces?), some say this is fully intended (addition of Brettanomyces or any other bacteria/yeast?).
The whole project above is currently on ice. No time for an investigation right now. The next step would be to get a pure culture from the organisms above and some simple fermentation tests.
Thanks for your comments, cheers Samuel
I believe the organisms you have are Brettanomyces. They certainly appear to be the correct morphology. If they were from a single colony then that are likely a pure culture. It is possible that the round cells are just a different form of the same beast as some yeasts can assume different morphologies under different conditions, even those living on the edge of the colony versus those in the center. Alternatively you could have a mix of Saccharomyces and Brettanomyces but unlikely if they are from a single colony. I did culture the bugs from some bottles of sours (Lambics) and found pediococcus, lactobacillus (I believe, not Acetobacter), Saccharomyces and Brettanomyces. Although there is not enough to make a positive identification, I think its likely that this is what you have.
thank you very much. I believe those cells are Brettanomyces as well. And Brettanomyces cells from colonies and cells from liquid cultures look very different indeed. The sample here was just some sediment from a fermenter. No pure culture for sure. I therefore expect some Saccharomyces impurities. I plan on isolating these Brettanomyces from the original beer one day to have a pure culture.
How did you differentiate the different organisms in your culture? (microscope, agar platings, PCR, sequencing, FISH etc.)