Wheat can be stored indefinitely if it is kept dry, cool and bug-free. It is best stored in smaller quantities, for example, five pounds or less per container. I have stored wheat in all types of containers and find canning jars or other glass containers to be best. However, plastic containers and foil pouches can also be used. One problem I have had with plastic containers occurred when the wheat got too humid and the weevils hatched. The weevils chewed right through the plastic containers and made hundreds of holes. Needless to say, it was a mess.
Metal containers are OK, as long as the containers themselves remain dry. Most metal containers, even No. 10 cans, will eventually rust in humid conditions. It is convenient to use No. 10 cans, if you have access to a canning machine.
Most methods of preserving wheat focus on preventing the weevils from hatching in the first place and keeping the wheat in an optimum condition. Two traditional methods involve coating the wheat with diatomaceous earth and putting Bay leaves in the containers. Neither of these methods is foolproof. Diatomaceous earth (DE) is a powder of the fossilized remains of diatoms, a type of hard shelled algae. DE is inert and can be eaten without harm to humans. When it comes in contact with insects, of any kind, the DE gets into the cracks in their chitin or shell and cuts it, the insect then dies. It is used by pest control companies to kill insects and spiders of all kinds. I have found it to be effective but not 100%. Bay leaves are only effective when fresh and will not stop weevils if the grain becomes damp.
The other methods of storage focus on depriving the organisms of oxygen. This can be done in a variety of ways, including putting dry ice into the containers until the container is full of carbon dioxide or putting in oxygen absorbing packets. Both of these methods are fairly expensive on a large scale. Another method involves injecting the grain in the containers with nitrogen. Once again, this is fairly pricey.
Opening the container usually compromises the protection, hence, the suggestion that the grain be stored in smaller containers.
I would prefer to store smaller quantities of grain, either in No. 10 cans or canning jars. However, larger containers, including plastic, are satisfactory as long as they are inspected periodically for failure.
Please feel free to add your own suggestions and comments.