Can frozen worm stocks be stored warmer?

Has anyone tried keeping their worms at -75 C instead of -80 C? One of our freezers just broke,
and the technician said keeping the freezers at -75 would be “much better” for them. Although we
imagine 5 degrees wouldn’t make a difference, I’m hoping to get some firsthand reassurance
before the big change.


I kept the worms for a couple of years at -70-(-65)oC. During that period, at least twice the freezer temperature raised to about -45oC. After three years in such conditions I successfully recovered the strains I needed.


yes…but I’m not sure if the difference in viability (and there will be as -196 is better than -80) has been documented by worm researchers.

What the technician says makes sense…if you run a -80 at -80 it’s at full capacity and puts the compressor through the ringer to maintain that temperature. Dropping by 5 degrees reduces the number of compressor cycles I guess and therefore the risk of compressor failure.

That said, any decrease in viability due to the higher temperature might be easily masked by variations in the procedures for freezing the worms…

I would freeze down multiple samples of wild-type worms at -80 and -75 and thaw them out at regular intervals over the next year(s) if you are worried. this would also give the background figures for viability based on your current freezing protocol / who’s doing the freezing.