I have the perfect opportunity to harvest and reuse, the same day. There’s a 5g batch that will be ready to go to secondary on Wed or Thu, and I plan on doing a 10g batch of the same APA one of those days. The way I look at it, the sediment on the bottom of the primary fermenter (Wye 1056) is just a big ass starter and I can divvy it in two and pitch it in the two primary fermenters…
Am I thinking wrong?
IMO, no.
Hah! Just found this…
No, I’m not thinking wrong, or no you can’t do that?
No, you’re not thinking wrong. Yet… ;D
Stay tuned, when I brain fart I do it right… ;D
Nope, nothing wrong with what you’re thinking.
mrmalty.com has a good yeast calculator.
You’ll probably only need 1/3 for each 5 gallons.
If you don’t plan on using any of the yeast cake within the next few weeks then I would recommend using some of the yeast to grow up an appropriate starter instead. This will ensure that the yeast is healthy, alive and ready to go to battle.
Yup, the boys were just explaining that on the BN episode quoted above…VERY helpful.
OK, so I listened to the BN-cast, read all there was to read on Mr Malty and read all the pertinent passages in the texts I consider relevant… Today I got the slurry out of the primary that I racked, thinned it, swirled it, and then (this is the hard part) decided whether it was thick or thin, and milliletered into the two fermenters I filled with todays 10G brew (same ale)…
It’s bubbling two hours later…scary… :o
Guess you pitched enough then 
That and the fact that it was alive and kicking coming straight out of a primary… REALLY going to town now. 8)