Back in october I harvested wild yeast from some wines grapes I'm growing in my yard, I brewed a small batch with it and it turned out well so I saved the trub/yeast from that batch in the fridge.
I recently woke the yeast up from itís cold storage slumber with some yeast nutrient/energizer and sugar water. That took off pretty well and the yeast set about consuming all of the sugar and flocculating out fairly quickly.
A little later I wanted to re-energize the yeast to contribute it to a batch of Wisconsin Weizen Beer being made as part of Discovery World Museumís Ale through the Ages program. I used a turkey baster to suck out the fermented liquid above the layer of yeast sediment on the bottom of my container. I dumped this liquid into a beer glass and refilled the container with warm sugar water to wake the yeast back up.
Then I neglected to dump out the beer glass containing the spent water. I tasted it and it tasted kind of like those ice beers that were all the rage in college, slightly beerish taste from the original batch of beer I brewed and high alcohol from the fermented out sugar water I added. There was a tiny bit of yeast sediment on the bottom from when I accidentally sucked some off with the baster. The liquid was clear.
Hereís where I admit to my colossal laziness. After about a week of sitting on my desk doing nothing I noticed that a small bit of the surface of the beer had an extremely thin film on it. Over the next day or two I watched as this thin film spread across the surface. After it had conquered the surface of the beer the film started to appear wrinkly and I took some photos.
It didnít smell like anything other than beer. So I left it to see what would happen.
Itís now been nearly two weeks since I filled the cup with this beerwater and the pellicle has thickened up quite a bit. I took some more photos.
As you can see itís yeast colored and looks like a creepy brain, itís about an eighth of an inch thick. The smell is of beer and yeast. Nothing sour or nasty. Which is a bit baffling considering this is sitting in an open to the air cup where any contaminant organism could easily fall in there.
The beer I made two weeks ago with the wild yeast doesnít seem to have any pellicle on it and it is still slowly fermenting away in my cold house (~55-58F). Perhaps the cold is part of the reason for the lack of infection?
I scooped a bit of the yeast brain out with a toothpick and gave it a taste, it definitely tastes like yeast. Any yeast geniuses out there know if this is Brett. or not?
Either way I think I will be saving this and brewing something with it.