Processed beans that are stored in ordinary containers will last around 10-14 days. Packaging at home using foil will extend the shelf life up to 3-4 weeks, whereas roasted beans packed in sealed four-layer paper bags can be stored for up to 6 months.
Depending on the type of coffee you are drinking, the amount of calories will differ significantly. Adding extras such as milk, sugar and syrup will all directly affect the calorie content of a coffee. A standard cup of black coffee (around 8oz) contains 1 calorie, but a cappuccino for example can contain anywhere from 60 to 160 calories, depending on the type of milk you take and the size of the cappuccino. For a low calorie coffee, switch the sugar to sweeteners, and switch full milk to skim or soy (or cut out the milk altogether!).