Storing them in your freezer is the best way. If you don’t have enough room in your freezer, I recommend storing them in a solid, air tight container. (such as Tupperware or plastic bucket). Since it’s not treated with any insecticide (and most all grains in the U.S. are), keeping pantry insects out of it will be your biggest problem.
Granary insects have been a problem with stored grain for thousands of years. The adults are small enough they can exist in your pantry, unnoticed by many. They lay eggs which are microscopic and hatch into larva that eventually grow into something large enough to be noticed (and quite unsavory). These larva are capable of burrowing through cardboard and soft plastic into grains or flours, or sometimes the eggs are laid undetected in hard storage container and then filled with a grain product. Today, in the U.S. most people have forgotten about this problem because most all conventional grain products are treated with an insecticide either at the farm it was grown on or shortly there after. This usually isn’t listed on any ingredient list because it is so common in the industry and assumed, even sometimes on products listed as chemical or pesticide free (since it’s added so early in the grain supply chain, before any processor even receives it). Everything we sell we also grow (except some minor ingredients in our baked goods). We handle it all the way from the time it’s planted (and usually also produce the seed it was grown from). Our grain has not been treated with anything to control granary insects and thus needs a little more care in storing. Freezing the grain occasionally and storing in a sealed hard container can control these insects.
Keeping the grains and flours dry is also very important. Temperature is not as much of a problem as are frequent temperature swings. If the temperature swings a lot daily, the moisture in the grain will migrate to the container edges. When the grain warms, some of the moisture comes out of the grain into the warmer drier air within the container. When the container cools, the addition moisture then collects on the cool wall of the container and condenses. After a number of cycles, the grain next to the container edges then becomes wet enough it can start to mold.