Frozen Yeast

Gremlyn1 said:

I've not used Wyeast before, but are these packets of liquid yeast? (as opposed to the vials from White Labs I am used to). I assume it's liquid, and personally wouldn't use them unless Wyeast is smart enough to add some glycerin to the suspension liquid. Gila, I'm positive that damage has occurred. Freezing will rupture the yeast cells, your viability is likely going to be so low that a starter would take quite a while to bring it back to usable levels. If I did go the route of using them, I'd make a starter and have it go a few days then let it start to settle (so the already ruptured and dead yeast cell matter would settle) and then repitch the decanted yeast liquid to another starter, which I would again let go a few days to ensure good viability and cell density. I am also assuming you don't have a microscope to verify cell viability...

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ThirdCity said:

Is it possible for dry yeast to freeze and die? I recently bought two kits. I have brewed one and rehydrated my dry yeast and pitched it. Over 48 hours later no signs of fermentation. So I opened a second pack of Munton's rehydrated it and added it (thinking that perhaps the first pack was bunk. Now over 24 hours later still no fermentation visible in the airlock or upon visual inspection of the fermenter. The extract kits (with yeast packets inside) travelled through the Midwest cold snap (-5 to 15* F) from Minneapolis to KC. Could dry yeast have been killed by the cold???

Any thoughts or suggestions would be much appreciated.

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