I'm doing a 5.5 gallon batch of Oatmeal Stout this weekend. The recipe recommended Wyeast London Ale III, so I have a pack waiting in the fridge. I've never pitched liquid yeast before, and I have a couple concerns/questions.
The OG of the stout is 1.047. The instructions say one package will be sufficient for up to 5 gallons. Since I'm actually doing 5.5 gallons, I punched in the numbers on Brewfather, and the resulting recommendation is 182 Billion cells will be required to do the job (1 pack of Wyeast contains 100 Billion). Even worse, using Brewfathers Yeast Viability calculator indicates that only 5% of the yeast in this packet would be viable (manufactured June 4, 2020.
Questions:
1) Am I better off just pitching TWO packages (i.e.: 200 billion cells)? How precise does this need to be?
2) Any experienced users of Wyeast and/or Brewfather - how accurate are those viability calculations? Does Wyeast really degrade to that degree (Wyeast advises using it within 6 months)?
The OG of the stout is 1.047. The instructions say one package will be sufficient for up to 5 gallons. Since I'm actually doing 5.5 gallons, I punched in the numbers on Brewfather, and the resulting recommendation is 182 Billion cells will be required to do the job (1 pack of Wyeast contains 100 Billion). Even worse, using Brewfathers Yeast Viability calculator indicates that only 5% of the yeast in this packet would be viable (manufactured June 4, 2020.
Questions:
1) Am I better off just pitching TWO packages (i.e.: 200 billion cells)? How precise does this need to be?
2) Any experienced users of Wyeast and/or Brewfather - how accurate are those viability calculations? Does Wyeast really degrade to that degree (Wyeast advises using it within 6 months)?