Viability of Frozen Yeast

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

mattrennert

Well-Known Member
Joined
Jul 15, 2009
Messages
53
Reaction score
2
Location
Platteville
Anyone have a rule of thumb for viability of frozen yeast? I have heard 5% drop per week for active yeast, I would imagine freezing slows the degradation..

Maybe 2% loss per week is reasonable?
 
Dry or liquid?

For liquid, freezing will kill the yeast. The ice crystals pierce the cell walls of the yeast. You would be lucky for any to survive unless you used a glycerin solution.

For dry - it will last for years. Dry looses about 4% per year at fridge temperatures, so would tale 10 years to be about 50% viability.
 
To be more clear...
I'm wondering about viabilty of frozen yeast yeast slurry in a solution with 15% glycerine, stored in a non-frost free freezer.
 
I don't know about the degradation, but I make vials with 5 ml yeast, 5 ml glycerin and 10 ml water. I resurrected a vial that a couple weeks ago had been frozen since 11/11.

I start with a weak 250 ml starter then step it up a couple more times. The 11/11 one started fermentation within 6 hours.
 
Back
Top