Good points Methyl, and if your freezer has a self-defrost function, don't even bother. You'd want a chest freezer that doesn't go through those cycles.

Storing in a cool dark dry place such as a root cellar is what I would do if I had to.

Another thing to think of is that much chemical degradation is tied to the amount of oxygen present.

Have you guys ever seen those nitrogen things that you use to preserve wine after the bottle has been opened? It would make sense to either replace the air in the mason jar with N2, or to just use those food saver bags that you can suck all the air out of.