Re-Pitch Rate? Cells Per Ml?

[davidg410]

I know there is a 250 page thread on yeast washing, but I can't seem to find a clear answer to these questions:

After yeast washing, i get between 20 - 40ml of very clean yeast. When calculating my re-pitch rate with Mr Malty

• Is the entire volume of the mason jar considered in the default slurry setting, or is it just the compacted yeast at the bottom of the mason jars?
• How many billion cells per ml do most consider accurate in washed yeast? I've read anywhere from 1.2 - 4.5.

 

[huckbof]

just use the slurry cake volume on the bottom
I use 2B per mL for that thick sluury cake

 

[flars]

Good information here.
https://www.homebrewtalk.com/showthread.php?t=519995
More good information on the WoodlandBrew site.

 

[DurtyChemist]

I don't count any assumption accurate. Without an accurate cell count using lab grade equipment you'll never know. I've pitched the same recipe on the entire yeast cake and ice used 1L starters on a stir plate from unwashed yeast slurry in a quart mason jar and it seems like the same results. Until I find that I've ACTUALLY over pitched and/or caused off favors I won't worry about over pitching.

 

[davidg410]

Good information here.
https://www.homebrewtalk.com/showthread.php?t=519995
More good information on the WoodlandBrew site.

Woodland Brew findings are very interesting. This was a huge help. Thanks!