How much yeast slurry to pitch, directly harvested?

[darlacat]

Hi,

I'm racking a porter I made with WYeast 1969 this weekend (1.050 OG), and intend to directly pitch some of the slurry from this batch into a dark mild I'm brewing the following day (est. 10.36-38 OG).

Anyone have any advice on how much of the fresh slurry to pitch? Most of the information online refers to starters made from rinsed yeast slurry.

Cheers!

 

[strange-steve]

Without lab equipment yeast pitch rates are essentially guesswork, all the more so when using harvested trub. It's all well and good working out that you need 150B cells, but without knowing the viable cell density of the trub then that becomes rather moot. The good news is that it probably doesn't matter all that much as long as you're in the ball park. I would guess that a couple of hundred ml of fresh slurry is probably enough, but really who knows?

 

[Cwrw666]

I usually use 3 table spoonfulls. Fermentation is usually slower to get started than with dried yeast floated on the surface (I assume because the dried yeast is in a more oxygen rich zone) and the FG is usually higher - maybe 1011 instead of 1010. So maybe a bit more would be better.

 

[Hanglow]

Assuming same volume of wort, I'd use 1/4 of the amount of yeast/trub mixture from your previous beer

 

[Surfingobo]

Take the busy mans option and pitch straight on top

 

[cushyno]

My guesstimates for immediate re-pitching are 250ml or about 1/3 of slurry.
Seems to work reasonably well at those rates.