Either large or small metal or plastic containers can be used, some containers seal airtight (others do not) e.g.: Metal or Plastic Rubbish bins. The containers that do not seal airtight must be lined with a heavy-duty food grade plastic bag, which with a tie can be made airtight.

The same day you buy grain, store it on a wooden floor or wooden platform of some sort. (NEVER directly onto a concrete or earthen floor.)
Next, place one or two bulbs of dried garlic inside of the container.

Our customers have told us that small amounts of either 3 or 4 bulbs of garlic and or an abundance of bay leaves inside the grain containers are excellent deterrents to weevils and other harmful insects. Please remember for weevils or insects to walk or move away the container must have an opening for the Garlic and or Bay leaves to do their work as a natural deterrent. And then some time later on when you are happy that no more harmful insects are left behind to eat the grain. The container may be sealed airtight. Now you are ready to store your grains in a dry place at home with minimum of temperatures changes. Be sure to check it on a regular basis when using Bay leaves and garlic as a deterrent.

For long-term survival storage it is important that grain should be stored in sealed container in an atmosphere of food grade carbon dioxide or nitrogen.
(Or even more simple, just buy a vaccum sealing unit from this site, listed under "Survival Products". )

On the same day that you take delivery of your grains, remove it from the grain bags and pour it right into you food grade clean containers. Which must either sit on a wooden floor or blocks of wood (NEVER directly onto a concrete or earthen floor.)

Use either Silica Gel or fresh rolls of natural toilet paper with the plastic wrapping removed and then place either the [Silica Gel in small mesh bags] or [unwrapped toilet rolls] inside the containers with the grains all around them. Silica Gel and dry unwrapped toilet rolls absorb moisture from temperature changes.

Having done all of the above right now you will be ready to seal your containers.

We are making the assumption that insects and or weevils have a change to walk away from the bulbs or Garlic and or Bay leaves located through the grains in the container first of all.

Or that you have put dry ice in the containers displace the oxygen in normal air with CO2 carbon dioxide. Or BOC the gas people have hired the CO2 or Nitrogen equipment for displacing the normal air inside the grain containers prior to sealing each container for survival storage 
 
 Alternatively, you  can spray Colloidal Silver on grain and allow to dry and then store. Ozonating grain also works. Bee products are never subject to bacterial attack: E.g. honey, bee's wax, bee propolis, royal jelly, etc. There might be an application with grain preservation.