This past harvest season I visited one of the largest hop storage and distribution facilities in the NorthWest. It was very educational, so I figured I would pass along what I learned. There seems to be a lot of myth and misinformation around hop storage and degradation. In commercial hop storage, hop are stored in bale form and almost all the bales have some kind of rip, tare or hole in them. They are not stored in any kind of air tight packaging. I inquired as to how long hops would last in storage like this. They said that they have had hops in storage for 2-3 years, in bale form, and tested them to find that they have not lost any of their qualities. The key to this kind of storage is that, the hops must be kept at 28F-25F and out of the light. They also stated that they have had hops in pellet form for 5-7 years without any losses. This is pretty amazing. What this means for homebrewers is that if we keep our hops in the freezer, they will last for several years with no worries.
Cheers!