One of my favourite brands of coffee, (Illy), which is a once in a while treat because of it's price, comes in a well-made aluminum can which has a screw-on lid with a plastic liner. The can itself has no plastic liner, but seems to be coated with something, probably to avoid the coffee from developing (no pun intended), a metallic taste. It is absolutely air and light tight. Does anybody have experience with storing chemicals in aluminium? Could there be a reaction? I've been reading this site on and off for a bit, and just subscribed because it's great to read about photography and its processes instead of electronic bits and software programs. And, the members are friendly and helpful.