I'm currently agonising over what to do with the pouch of A-09 I'll be using in my next brew - next 2 brews actually...
(I already know exactly what you'd do!
)
It's over 4 months old and according to the Brewers Friend calculator dead as a doornail with 0% viable cells!
I don't believe a word of it, I'm 100% confident if I pitch it it'll be reet, especially in my smaller 12L batches.
I've a slight concern that I don't want to massively overpitch if it is still very viable, and likewise don't want to underpitch either.
Even a lazy-*** brewer like me knows it'll be a safer bet to wake it up with a starter. So, shock-horror, I might actually do it your way for once!
Overbuild it, then I can scoop out a few carefully calculated and calibrated tablespoons of thick flocculated yeast for brew #1 and leave the rest behind for brew #2