How to determine what is slurry

Brewer #360286

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I am trying to use the Yeast Pitch Rate calculator and i am not sure what the slurry is , is it all the stuff left over from my brew , or is it the yeast that settles to the bottom of the jar , after washing it , its very confusing , i can not seem to find out
 
Hm, I can't say what exactly the BF calculator thinks it is, but it seems to work fine when I think of slurry as the goop from the bottom of my fermenter. Unwashed, just scooped into a mason jar best I can and it settles into a layer of liquid (the supernatant) and solids (the yeast slurry, perhaps with some trub or hops residue). In homebrewing, washing generally does not add value to the yeast slurry.
 
Just had a look calculator gets you to input slurry density. I go by half of pure pitch.
Eg 1ml of pure yeast =~1 billion cells.
If I've got 250ml of slurry I expect 125billion pitch.
This is for fresh slurry too. Cell count drops 10% / month. If were two three months old I'd spin it in 1.5lt or wort for a vitality starter.
 
There's a Mr. Wizard answer somewhere in the BYO archives... I asked the same question! There's really no definitive answer but the write up gives some guidelines.
 
There really isn't any definitive answer here, as slurry density varies wildly with the type of yeast you have, how flocculant the yeast is, and what the yeast cell size is.
 
I’ve just used whatever default for slurry in the calculator and it’s always turned out pitching the amount it says.
 

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