German Brewing

Your sheet calculates total cells based on 50 ml of slurry and then calculates cells/ml based on 27.5 ml.

Wyeast is stating that 27.5 ml will have 1.4 x 10⁹ cells/ml.

That's all I'm saying. I don't know where the leap to 100% more cells comes from.

Think of it like cells per ml of a sample -vs- cells per ml of just the yeast solids. If you decant the liquid off the top of a 50 ml sample once the solids have settled, you are left with 27.5ml of yeast slurry, totaling 7e10 total cells, or 2.55e9 cells per ml. This is why cells counts go up with % solids (R² = 0.99955), because the solids are the cells (and some trub). This allows you to estimate how many ml of slurry you need to reach a target pitching rate, rather than pitching the entire loose/dilute slurry.

They way they word it on the Wyeast website makes it unclear whether they refer to 1.2 x 10⁹ cells/ml as referring to the total sample volume or just the volume of solids.

Tricky tricky.

The R square tells you this. The uniformity of # cells per ml (solids) confirms it as well. There should be the same number of cells in a defined (1ml) volume.

Potato, po-tah-to.

Thanks for the data points though.

I realize I'm beating my head against the wall with you bc you are happy with the way you do it. That's fine. I'm putting the info out there to clarify previous statements for everyone else. The estimate of 1.2 billion cells is of no use, for example, if you pour off your yeast cake and there's only 100ml of actual yeast that settles in a 1L jar. But, if you pour off the liquid, then you know you have 250 billion cells to work with and can dilute to whatever concentration you want.

I imagine that most people shoot for a consistent amount of slurry that corresponds to 40-60% of a 1 qt. vessel. If that's the case, then 1.2 x 10⁹ cells/ml is the manufacturer stated slurry amount.

I 100% agree with you that if for some reason or another you end up with varying amounts of yeast solids in your different batches that a more dynamic approach would be necessary. I should have clarified that at the outset but it was through this dialogue that I realized that was what I was trying to say.

Sorry for any confusion.

I think people pour what's in the bottom of the carboy into a jar to keep for later.

All Wyeast did was count yeast and create a standard curve for us.

I did a delicious 90/10 Pils/Vienna (no cara or specialty malts) last summer, but that was pre-LoDO. I have every intention of trying it again soon with low O2 (though I might throw in a dash of Carahell).
I am a big fan of Vienna. I use it in almost everything (goes great in a NEIPA).

I can definitely taste a bit of Vienna in this one. It's subtle though.

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