Your yeast has been frozen in the worst possible way, very slooowly. This creates large ice crystal formation within the yeast cells which have a severely damaging affect on the yeast cells and their ability to ferment the dough. Also, you are probably leaching out a fair amount of glutathione (a reducing agent much like L-cysteine) from the damaged yeast cells. This will have a softening affect upon the dough, creating still more problems, if inconsistent fermentation and rise of the dough wasn’t enough.
Pitch the damaged yeast. This might be a good time to change over to IDY. You can’t hardly hurt that stuff, and it keeps for a year or more when stored at room temperature so you aren’t using valuable refrigerated space for your yeast storage.
Tom Lehmann/The Dough Doctor
