An update on my 10 liter dewar - it's empty. Sat (Aug 22) I checked and while it was still cold inside there was no liquid LN. My sister was here and I tried to pour some LN into a container to freeze chunks of apple to break, and maybe make some ice cream. Nothing but vapor would pour out, no liquid. That was 9 wks. I think somewhere between 8 and 9 weeks the liquid went away, but it was still cold enough inside to treat a small blade. I think I can count on 8 weeks and I'm happy with that.