Assuming you're talking about storing roasted coffee beans in a bag, there are a few things to keep in mind. First, storage location is key. You want to store your coffee in a cool, dry place away from direct sunlight or any other source of heat. A pantry or cupboard is usually ideal. Second, an airtight container is essential for keeping your coffee fresh. Once the bag is open, transfer the beans to an airtight jar or canister. Finally, while whole beans stay fresher longer than ground coffee, if you know you won't use a whole bag within a week or two of opening it, go ahead and grind what you need and store the rest as whole beans.