When we bought in bulk we stored it in 55 gal barrels like Caprocker. Try to keep the barrels full. Even sealed barrels will cause the moisture in the corn to evaporate and then condense in open areas inside of the barrel.

The one thing to be sure of is that it cannot get wet, Corn will mold in a hurry, even corn that in plastic bags can mold. Large shifts in temperatures will cause the moisture on the corn to condense inside of the bag and start to mold. Weevils are something else, a natural vermin in the corn, and when they decide to hatch there is no stopping them.