When I brewed this past weekend, I passed on 3 vials of yeast that my LHBS had in stock that were due to "expire" on 12/30/09. I knew he was getting new yeast in on Friday so I waited because I wanted to make a smaller starter. But, it got me thinking about viability when you grow the yeast count.
When I put 8/30/09 into the date in www.mrmalty.com, I get a viability of 22%. That means 78% is shitty yeast, right? So, if I dump 1 tube into a 1 liter starter, would I have double the amount of 22% viable yeast? Would I have a 1 liter slurry of 44% viable yeast?
Obviously, I would use more vials and/or step up the starter but I'm just curious as to how it works. Sure, I can just do as the pitch rate calc says to do but I like to know the "why" behind things. Knowing why allows for exploration and troubleshooting, if need be.
