Especially knowing how many cells to expect per gram of sediment allows me to skip the counting and simply estimate yeast density by weight.

I've begun weighing the refrigerated compacted yeast sediment for my stir plate starters as well, and I'm coming up with numbers that seem much larger than possible. As I don't have hemocytometers and microscopes and such, at this point it is simply a mystery for me.

For instance, for a 10 gal batch of O.G. 1.056 I'm aiming for pitching around 350 B cells of WLP001. Use a stir plate starter of 2.15 L of 1.040 wort created from RO water + 245 g DME. Boil 15 mins. Hot trub is decanted off with RO water top up after to arrive at the 2.15 L at 1.040. Chill and pitch 25 B cells (1/4 vial of WLP001). I use a gentle stir plate setting, where I crank it up till I hear the pinging of the vortex off the bar, then back it down a little till only occasional pinging. Ferment to completion (F.G. 1.012). Refrigerate for 2 days at 2 deg C. Decant beer completely. Add pre-weighed amount of room temp wort. Resuspend yeast cake. Pour out and weigh mixture. Then, of course, pitch this into batch.

I get 80 grams of sediment. From existing literature, I calculate that, at most, there's about 8 g of trub present. Pobably much less, given that I decant the hot trub. The yeast cake is very dense. I can upend the vessel and the sediment stays put. So, you would think this would be a high density, around 7 - 8 B/g. But this gives a total cell count around 560 - 640 B cells. Way high from target. If I have, in fact, arrived at my target, then my density is 4.4 - 4.9 B/g for WLP001, which seems too low given the level of compaction.

Could you share some of your numbers based on weight of yeast sediment from single step starter for some yeast strains so I could get an idea of the size of the ballpark?