Hi Rick, 

I've seen people use the term "dry canning" to mean different things (many of which are unsafe) so I will lay out a couple of scenarios to help you find a safe method for storage for your grain.

First, it is safe to store fully dried grains, seeds, and beans in canning jars. You can use a vacuum sealer to remove some of the oxygen from the jars, and you can also add oxygen absorber packets. No heat and no moisture is used in this process, and it is a safe method.

A second method that has been popular in some internet circles is to heat sealed canning jars filled with dry grain in the oven. This method is not recommended by the Extension Service. Dry oven heat is damaging to glass jars. Dry heat that works through conduction rather than convection currents is also not an effective way to heat the contents of the jar quickly, and it cannot be guaranteed to pasteurize insect eggs in the grain (one of the supposed benefits). This type of "dry canning" also runs the risk of pulling residual moisture from the grain and trapping it in pockets where bacteria can grow. This method could be dangerous.

Lastly, I should not that there are no tested processes for canning fully cooked or hydrated grains at home, whether in a pressure canner or heated another way. Cooked grains should be refrigerated or frozen for long term storage. 

You can read more of the reasons behind these recommendations at the National Center for Home Food Preservation here: https://nchfp.uga.edu/blog/dry-canning-isnt-canning-to-me

Thanks for using Ask Extension,

Jared