Sunday, June 19, 2011

Wild Yeast Microscopy

Here are a few photos of the wild yeast I captured from my backyard. They look like pretty standard yeast to me - not sure I can tell much more simply based on their physiology (Brettanomyces? Saccharomyces?). I'm no microbiologist, but they appear to be in pretty good shape; I think there are even some showing some budding. Some rough measurements of the cells give cell lengths of 9-11µm and widths of 4-7µm. I'm not entirely sure what the smaller "specks" are - they seem too big to be bacteria, but I suppose they could be. I recently brewed up a relatively simple "saison" with this culture that is happily fermenting away at the moment (post and recipe here).

All photos were taken with a Nikon D90 mounted on a Nikon Eclipse TS100 inverted microscope at 400x total magnification.

(click on each image for a larger version)




9 comments:

Jeffrey Crane said...

very cool.
I'm jealous of your microscope.
Have you compared your pictures to other yeast pictures? Here is one that I know of.

http://brettanomyces.wordpress.com/2010/06/30/brettanomyces-yeast-cell-images/

And there should be some on this site soon:
http://sciencebrewer.com/wild-yeast-project/

From what I have heard the best way to tell the difference between Sacc and Brett is by the size of the cell. So you may need to take a picture of a scale and use it to figure the size of your cells.

Jim Lemire said...

Well, it's not my microscope - a colleague was nice enough to let me use his. It's nice to work in a university biology department!

I forgot to include the measurements I took (I've added them in now). Rather roughly, the cell lengths are 9-11µm and the cell widths are 4-7 µm.

I'll check out those links - thanks!

Jeffrey Crane said...

I also just found this site that has some great photos of bottle dregs.
http://saccharolicious.blogspot.com/search/label/brettanomyces

Adam said...

I know this is fairly late compared the post but it looks to me like you might have some brett in there also. The smaller ellipsoidal cells look like many bretts I've seen under a microscope. The next step would be to have the culture tested on some LCSM. I could do it for you if you wanted to send me some culture. I do yeast testing for a brewery weekly and always have a few left over LCSM plates. Even further I can easily grow up an isolated colony from what grows on the LCSM plate. That way you have a pure culture of non-sacch yeast to use if you'd like, which you captured yourself.

Jim Lemire said...

Adam - that would be spectacular! Shoot me an email with details.

Thanks.

sciencebrewer.com said...

Just caught wind to this post! Nice images! How did you attach your D90 to the scope? I have a D90 and would be fun to tinker with.

As for your images...

You definitely have some Brett but also some other wild yeast I can't easily identify. Seems like you have a mixed culture there. Also, you have a significant number of bacteria as well, bacilli and maybe pedio in particular.

Cheers and let me know how the brew turns out,

J

Jim Lemire said...

J - the camera was mounted on a camera port on the third ocular of the scope. I'm not sure what sort of adapter was needed since the wholeetup belongs to a colleague who simply let me use it (he's a marine phycologist). I can find details if you want.

I assumed that the culture was mixed - I didn't even attempt to plate and isolate anything. I just grew up whatever happened to fall in the starter wort. The beer turned out much, much cleaner then I ever thought it would. I'll post some tasting notes soonish.

Just out of curiosity, how can you tell that there are Brett and other wild yeast? Are there some basic characteristics you use?

JC Tetreault said...

Hey Jim, would love to try your beer: jc (at) trilliumbrewing (dot) com

Jim Lemire said...

JC - would be happy to share...looking forward to meeting up soonish up there at Trillium

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