MgSO4. Microwaveable? Why add after autoclaving?

Hi I’m wondering first if I can microwave a freezing mix (glycerol/agar) containing MgSO4.

Why is this added after autoclaving media? Does it react with something else at high temp? I know E. coli growth is limited without it, but do worms need this to survive?


what springs immediately to mind is;

  1. why would you want to do that?


  1. that you should read this series of posts which covers the reason for adding MgSO4 after the autoclaved agar has cooled to ~55°C,


  1. I have a stock of soft-agar freezing mix I wish to aliquot.

  2. I think I found the post you were referring to (
    So I can’t heat it, nor melt it. I’ll try to pipette it out, or make new.

Thank you very much, I am happy to know why we add all those things post-autoclave!

er…yep, sorry that’s the link that I didn’t include…