Having trouble deciding how to add glycerine to freeze my yeast. Probably overthinking this one.
Cooked up some starter from a factory vial, so I'm still on fresh yeast in the first "generation", so to speak. I estimated a 1.5b / g DME cell growth rate. Used a fresh ~100b vial of WLP029 with 380g DME, split it 8.25 ways, and pitched 3.25 back for stepping up to a 11 gal batch it went into last week. That leaves me with 5 vials of ~58b cells each which have been sitting in my fridge for a week.
Here's a picture to better illustrate. Can't see the 5th vial hiding in the back.
(Ignore the factory vial of WLP007 in front; it's for next week's IPA starter. The wife brought it home from the brew store without an ice pack and left it out for an hour, and I wanted to cool it quickly.)
Should I:
#1- Pour off half of the liquid from, then add about 25% volume of gylcerine, and freeze. (58b per vial, ~25% empty headspace)
#2- Pour off most of the liquid, agitate back to a slurry, condense down to 3 vials, and add 25% volume glycerine. (96b per vial, ~25% empty headspace)
#3- Same as #2, but condense down to 2 vials. (145b per vial, ~10% empty headspace)
Cooked up some starter from a factory vial, so I'm still on fresh yeast in the first "generation", so to speak. I estimated a 1.5b / g DME cell growth rate. Used a fresh ~100b vial of WLP029 with 380g DME, split it 8.25 ways, and pitched 3.25 back for stepping up to a 11 gal batch it went into last week. That leaves me with 5 vials of ~58b cells each which have been sitting in my fridge for a week.
Here's a picture to better illustrate. Can't see the 5th vial hiding in the back.
(Ignore the factory vial of WLP007 in front; it's for next week's IPA starter. The wife brought it home from the brew store without an ice pack and left it out for an hour, and I wanted to cool it quickly.)
Should I:
#1- Pour off half of the liquid from, then add about 25% volume of gylcerine, and freeze. (58b per vial, ~25% empty headspace)
#2- Pour off most of the liquid, agitate back to a slurry, condense down to 3 vials, and add 25% volume glycerine. (96b per vial, ~25% empty headspace)
#3- Same as #2, but condense down to 2 vials. (145b per vial, ~10% empty headspace)