Larry, you probably know all this already, but I'd like to say it again in this thread.
Glass or plastic jars (or maybe gallon freezer bags) will prevent condensation from reaching the frozen contents IF, every time you take a jar out, you let it warm
all the way up to room temperature before opening it. I found that to be a royal pain in the butt!
The change from, say. 15% RH to 30% RH in the trapped air is a tiny amount of water, but even a drop or fog of liquid condensation is a relatively huge amount. Without a desiccant, allowing
any room air to
condense inside a jar and then putting it back into a fridge probably assures 100% humidity. That's my opinion, anyway. If I were freezing seeds or using cold storage, I would only do it with containers I knew I wouldn't open more often than yearly, AND I would use a desiccant in each container.
I like having a "humidity card" in each tub so I can see when the silica gel is exhausted. My room-temperature tubs don't seal perfectly, and I keep having to replace the desiccant.
Modern no-frost freezers have some strong drying mechanism that prevents frost build-up, and causes freezer burn, a.k.a. severe dehydration. Apparently 15% RH is the ideal humidity for long-term storage, but at some point below that, some or most seeds can be harmed by TOO dry storage.
http://garden.org/ideas/view/R...
pink/blue Humidity cards:
Drierite Relative Humidity cards at 40 cents each:
https://secure.drierite.com/ca...
ULINE humidity cards, $50/250 3-spot cards or $70 / 400 6-spot cards
http://www.uline.com/BL_1002/H...
http://www.uline.com/Product/D...