Originally Posted by diS
As I said I didn't count it, it is estimation based on wyeast suggestion. I contacted them about it and Jess from lab says that it should put me in ball park.
I am open to new cognition's.
We are probably just splitting hairs here. In all practicality a factor of two on the cell count is not a big deal. I see a variance by a factor of 6 in density of "thick slurry" and between 60%-97% viability from freshly harvested cakes. This seems to be a common finding by people doing cell counts. The combined error when pitching from a slurry is over 10 times just between these two variables.
I just am trying to understand where the difference comes from. Perhaps the yeast from their lab has much less additional material such as protein. Under the scope I can see that there is about 10-25% as much protein mass as yeast cells. (That's just a complete WAG at it based on relative size. You can see it to the top and right of this image:trub
Perhaps 1 billion cells per ml is more accurate for slurries, and 2 billion cells per ml is more accurate for the material that comes out of a WYeast package.