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Counting Yeast Cells

Any one have some advise on where to start and what equipment one would need.

Myself and my wife are moving into commercial brewing and i would like to accurately determine cell density when reusing a yeast cake.

Microscope, hemocytometer and hemocytometer cover slip, pipette, flask, and a hand-held counter.
You can stain with Methylene Blue or Rhodamine B to test for viability, but there has been some debate about the accuracy using that method. Staining for viability is a less reliable method than using a slide culture, with which you can count the number of cells that bud and produce daughter cells. Plus, as the percentage of viable cells decreases, so does the accuracy of the staining test.
Fluorochrome stains are now one of the more accurate methods in determining viability of
yeast cells, but the requirement for a fluorescent microscope can make the method pretty expensive.

I recently came across a free microscope and rigged a light up to it to try to start doing this. I then bought all the other equipment on amazon which can be done cheaply. I’m not sure if it is the light on my microscope or the cheap hemocytometer but I am having a bunch of trouble actually counting the cells because I cannot really see the grid lines. I’m thinking it’s the light because I can see them faintly before I put any yeast samples in the counting chamber. Or maybe it is a combination of both because I did buy pretty much the cheapest hemocytometer out there.

Either way, I used the Wyeast book as a reference and was planning on nerding out with this yeast counting to check the viability of my frozen yeast samples.

you might also go over to www.probrewer.com they can probably steer you in the right direction.

The Brewing Science Institute has a great Brewery Lab Handbook http://brewingscience.com/PDF/BSI_brewe … ndbook.pdf .

[quote=“mplsbrewer”]I recently came across a free microscope and rigged a light up to it to try to start doing this. I then bought all the other equipment on amazon which can be done cheaply. I’m not sure if it is the light on my microscope or the cheap hemocytometer but I am having a bunch of trouble actually counting the cells because I cannot really see the grid lines. I’m thinking it’s the light because I can see them faintly before I put any yeast samples in the counting chamber. Or maybe it is a combination of both because I did buy pretty much the cheapest hemocytometer out there.

Either way, I used the Wyeast book as a reference and was planning on nerding out with this yeast counting to check the viability of my frozen yeast samples.[/quote]
If you see them faintly, try adjusting the contrast by playing with the iris. It’s hard to steer you in the right direction without knowing what features your scope has. It’s most likely fine tuning your light.

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