Mason Jars:

Tobacco in jars (or any sealed container including tins) will lose moisture until the air inside reaches stasis, so if you open them, even for a second, you will lose moisture. The smaller the amount of tobacco in the jar the faster they lose moisture (more air to humidify to stasis). Their seals aren't perfect (they're cheap items) so check them visually by tumbling. The air and tumbling keep them in a 'decanted' or oxygenated state that's excellent for smoking.

This dynamic can be altered by heat. Best place is cool, dark so basements are generally ideal. No fridge needed.