Eureka, this is the third post in the pentade about some agar plates. The other two posts about dregs and Lactobacillus can be found here. Today, some pictures of brewers yeast Saccaromyces cerevisiae. I plated Wyeast’s #1056 American Ale and #3787 Trappist High Gravity yeasts a while ago on Sabouraud agar and now its time to have a look at it.
#1056 American Ale
#1056 American Ale yeast on Sabouraud agar after three days of incubation.
Could observe just one sort of colonies after three days of incubation: Off-white color, even, circular, glossy, convex, 2 mm diameter. Typical yeast morphology.
Microscopy picture #1056 American Ale yeast colony
And the microscopy observation confirms that the colonies are indeed yeast cells. This is a very typical picture of the slightly oval yeast cells. But let me just add some further information that can be derived from the picture. Not only is it possible to identify these cells as yeasts, but it is further possible to identify this particular yeast strain to be top fermenting. Top fermenting yeasts tend to stick together, bottom fermenting ones don’t (or less). Unfortunately, I do not have a picture of bottom fermenting yeast cells available right now to show the difference.
#3787 Trappist High Gravity from 2010
I have a sample of this yeast strain in my yeast library since 2010 and I originally isolated this strain from an agar plate. As I was not sure if the yeast was really pure (had no microscope yet), I plated it and hoped to get an answer.
#3787 Trappist High Gravity yeast on Sabouraud agar after three days of incubation.
And there were just one sort of colonies, so far so good: Off-white color, serrated, irregular, glossy, flat, 2 mm diameter. Some look like snow flakes. Well, this is a bit strange. I expected the colonies to look like those in the picture of #3787 below. The colonies look very similar to those from the 3 Fonteinen dregs.
And the microscopy analysis identified the colonies to be bacteria not yeasts. I have no picture of the microscopy sample as it is really difficult to get a good picture due to the really small size of bacteria. This means that my #3787 from 2010 was indeed not pure.
#3787 Trappist High Gravity from 2011
I brewed a batch of Belgian style Ale in 2011 and as I was not really sure about the quality of the yeast strain in the yeast library (see above), I got myself a fresh culture of #3787 Trappist High Gravity to be sure.
#3787 Trappist High Gravity yeast on Sabouraud agar after three days of incubation.
Just one sort of colonies on the agar: Off-white color, even, circular, glossy, convex, 2 mm diameter. Typical yeast morphology again.
Microscopy picture #3787 Trappist High Gravity yeast colony
And again the typical yeast cells in the microscopy sample. I observed something interesting as well. Look at the colony in the middle of the left side, the one which looks like a club. I already observed a cell like this before in the BFM dregs analysis a while ago. See Fig5 in this thread. This would mean that there could be some yeasts in the dregs as well. And this is of no surprise to me as I took the dregs out of a fermenter and there could certainly be yeast cells in the bottom of the fermenter.
So far so good. Because I had some cool results in the past two posts and not in this one yet, I kind of tried to shoot a cool picture of yeasts. I already mentioned, my microscope and camera are not the best ones. But they do their job. One thing that is really difficult is to look at the samples with the highest magnification of 2000x using the immersion oil objective. And to take a photo of such a magnification is even harder. But I did my best to get the following picture.
Microscopy picture #3787 Trappist High Gravity yeast colony
I think it is a quite good picture. And you can even see the club-formed cell as well. I like this picture very much.
Well, that’s all about Saccaromyces cerevisiae so far. I hope some of you enjoyed the pictures as I did and maybe learned something new. If someone noticed that I did not mentioned anything about the Heidelberger Kellerhefe, although mentioned in the first post, well, the yeast seems to have finally given up on me. I could not observe any colonies, even after further incubation…
The next post about agar will be about Wyeast’s #3763 Roeselare Blend culture(s). And there will be some cool results, I promise. And I just decided to post some pictures of top and bottom fermenting yeasts in the future as well to show the differences. Feel free to comment below anytime. I really appreciate it.
Eureka Brewing 
I’m amazed at the amount of things you do! I mean if this blog is any indicator, it looks like you’re constantly brewing or are glued to the microscope. That’s some passions right there…
Well, this is just an illusion. The most of the posted recipes are from the last years. But I can’t deny that I have a tight brewing schedule. Brewed two batches last week already 🙂 And about the microscope. I have some spear time at the moment as there are no lectures at the University, just exams to pass 🙂 This gives me some time to do other stuff. So I did some agar plates and use the microscope to help me with the identification of the colonies.
I hope I can do some plates with your potato agar in the future but I will wait until I finally get my pure Brettanomyces strains from Wyeast.