I don't know about the freezer. In 1999 I bought about 20kg of flour. Put it in a see through plastic box with a clamp lid. Not airtight but tight enough to prevent anything coming in or out. We are now baking bread from that flour and no weevils, creepy crawlies or other nasties. The expiration date is (HA!) 2002 so if that's anything to go by we should have dropped dead a few months ago ;-) Maybe we were lucky to purchase flour that didn't contain anything to begin with. Maybe the container prevented anything from hatching. If there were threads developing in there it would be fungii so inedible. Bit the flour smells good, bakes good and tastes good.
Bought a Dutch oven today. When I figured out how it exactly works will bake some bread from that very flour and see how it comes out.
Other dry products we've put in a large 120litre barrel with a very solid clamp lid. All the grain is in such barrels too. Really no way for moist to get in. Heard about people here who fill such barrels (blue with a black lid and metal clamp) and send stuff to family in Suriname. We've got 5 of such barrels and might get more for water-storage.