Originally Posted by bsay
How do you know they are not frozen? If you are expecting ice crystals on the inside, well that's exactly what the glycerine prevents. Try filling a spare vial 1/2 full of water, and place in the center of your yeast vials. If it freezes, then all is well.
I guess I expected the slurry to still freeze, though I don't know why... I guess I didn't see it mentioned anywhere that it wouldn't.
I'm sure that a vial with water would freeze, as everything else in there freezes fine, so I guess it's OK!