I got two vials of white labs yeast both completely frozen. Has anyone had any luck reviving frozen yeast? I’m finding things from 10% loss of viability to the majority of the cells have ruptured
I don’t know if this will help but I purchased WYeast from NB and even sent an e-mail asking them how the yeast will react to being shipped in the cold before I purchased the yeast and their response as along the lines of “freezing liquid yeast is not bad for the yeast, it just puts them in hibernation. Let the yeast thaw out in the fridge for three days before breaking the pack and be patient while the pack swells.” I did just that and it was like the yeast was never frozen. Granted I could not see inside the pack to see just how frozen the yeast was but maybe this will give you some hope if no one can give you an answer. You could also make a yeast starter to a) check to see if the yeast react to the extract and b) help the yeast before you pitch it since it was frozen.
A couple of days ago I received a shipment from NB. The pack of WY1056 was partially swelled and had chunks of ice in it. Made a 1.5 liter starter yesterday morning. The starter took off in a few hours with a one-half inch thich krausen.
I don’t think the yeast was set back at all.