Ohio State University has published a fact sheet regarding grain Weevils that says keeping grain at 0*F for 4 days will kill any larvae that is in/on the grain.
Forrest has eluded to this as well.
Moisture on grain is not necessarily a bad thing either, as long as it is controlled. Moisture on the husk improves it's friability thus allowing it to split open during milling rather than shear. I am not saying that your grain should be stored wet but, many discount the idea of freezing grain due to the condensation aspect. As long as the grain is kept frozen, the condensation won't cause mold.
That said, I freeze my sacks for the 4 days and then store them at room temp in a garage in an air tight container. I have never had bugs or mold.