The seal-a-meal appliance has a special lid you can use with their vacuum pump to vacuum seal canning jars without heating the contents.
You could take up to 1 gallon sized jars filled with the grains and then vacuum seal them.
I’ve read somewhere that some people put a chunk of dry ice into jars before sealing them to replace oxygen with carbon dioxide to prolong the shelf life.
Haven’t tried it, maybe someone on the forum has?
Here’s something cool (Man I need to add this to my Preparedness Manual, oh well maybe the next update)
“The Alvin” Vacuum Sealer
http://www.instructables.com/id/The-Alvin-Vacuum-Sealer/
Shows how you can rig a Brake Bleeder Vaccum Pump and the Food Saver Jar Sealer to seal canning jars if you don’t have electricity.