I get asked a lot about how to store coffees once roasted. Freezing, vac sealing, canning, you name it, I have heard it. So here is a bit of advice for those using fresh coffee:
Oxygen is your enemy. Do not use anything with head space for storage. Canning jars with the nifty valves do not work. Even small amounts of Oxygen expedite the coffee's volatiles toward flavor degradation. For oily darker roasts, it can even speed up the development of rancid flavors so think about keeping the air out.
Moisture is very bad. Freezing can be fine but if you don't protect the coffee from condensation adequately, moisture will contaminate it. Much like green coffee, humidity is always a contamination problem but it is the day to day variance in humidity that presents the biggest problem. Reseal if you can but think about a storage space with the idea of keeping moisture out.
Heat is not a good thing. I shouldn't even need to explain this one. Store your coffee in a cool dark place at a very controlled and consistent temperature, not your counter top by the kitchen window...
So there, it's really simple. If you are one of those low consumption coffee drinkers who needs time to work through a bag, get a vacuum sealer like a food saver canister or one of the hand pump vacuum canisters that's so popular right now. Either put your coffee in the fridge or a cool pantry/wine cellar and pay attention. It's not milk but treat it as such and you can be assured if it wasn't good on day 5, it wasn't something you did in storage.