Friday, 20 March 2015

Oude Bruin (Roeselare) Microscopy

I've brewed a lot of lighter sour beers, and I have a 60L carboy with a lambic-style solera, so I wanted some sours with...moooore... I wanted toast, roast even, and caramel, and malt behind the sour and funk characters! I found La Folie from New Belgium brewing to be a little ridiculous sour with not enough funk or malt flavor getting past that puckering. I will release the recipe and full tasting notes probably much later this year after bottling, but when I took a sample it was deliciously toasty and had a decent tartness for the fact that it's only 5 months old, but I can tell you for sure that it is fermented with Roeselare, as well as Tart of Darkness dregs from The Bruery (Fucking amazing beer, so sour!). 

So, through my forgetfulness I let the airlock on the oude bruin dry out a bit too much and I think that a bit too much oxygen got in because the pellicle was starting to get pretty thick even after just 5 months. I was really paranoid about acetobacter, so I took the sample to taste (no vinegar), and took a sample into the lab to take some images.

I took 2 ml of the beer and centrifuged it down at 10,000 rpm for 5 minutes to pellet the cells a bit, since I thought the cell count in the beer would be pretty low. I resuspended the pellet in about 50 ul of the beer and wet mounted it on a slip. I put it under an inverted DIC microscope and used oil immersion with 60x objective to get these images:

These two pictures are of the same stuff but in a different plane of focus. I think that those big thick elongated cells are Brettanomyces lambicus from Wyeast especially when comparing it to Eureka Brewing's microscopy of it. The lower picture was to show those very small round bacteria (coccal morphology) which I think may be pediococcus.

More brettanomyces lambicus from the roeselare blend, and another more round cell near the bottom of the frame which may be a different yeast, but there's no way to tell. 
This lemon-shaped cell is a great example of what I've been told is classical brett morphology: kind of pointed at the ends and not nice and spherical like saccharomyces.

There are very long cells here, which I think are still the same wild yeast exhibiting pseudohyphae formation.

In this video I wanted to both show the movement inside of the long yeast cell. I have no idea what that compartment is in the cell, if it may be the nucleus and the nucleolus, or is it just a large central vacuole? (DIC can give inverted looking images where protruding parts can look inverted) I love yeast, but to be honest I've never actually learned much about it at school.

In this one, I wanted to show that little rod shaped bacillus in the upper left quadrant which seems to be wriggling around. I watched it move for a while and I'm curious if it was truly a motile bacteria or not. I'm not much of a taxonomist so I wonder if it might be lactobacillus or acetobacter?

Questions? Comments? Answers or Ideas?

Thanks for reading!

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