We are having a really hard time finding a truly airtight bin large enough to keep at least 50 lbs of bulk grain in. Does anyone have any suggestions? We keep our grains in the shed and want to keep out mice and bugs.
Homebrew Finds has a nice roundup of all the options. I use food-grade 5 gallon pails and Gamma lids that I got from Menards (the cheapest way to go that route, if you have a Menards nearby), and I've never had problems with bugs.
I just found an even better solution than a locking trash can. Sometimes mice can even squeeze through the tiny openings or chew through the edges of a locking trash can. My husband and I recently started using large pet food containers designed for horse food. It's made from a very thick plastic that even rodents cannot chew through. The lid screws tight for an air tight seal and the plastic is food grade/non BPA.