Like most food items, coffee has a shelf life. It stales and loses its character, body, aromatics, and flavor. When possible, purchase smaller amounts of coffee that can be used within 21 days. If you prefer to buy in bulk to save on shipping or to avoid an extra trip to the store, keep the coffee in a dry, cool place and avoid exposing it to the air. Portion a large bag of coffee into smaller bags to avoid exposing the entire lot every morning.

Also, coffee is 99% water, so it stands to reason that if you use poor quality water, your coffee will be bad. A simple rule of thumb is that if you don't like how your water tastes, don't use it to brew your coffee. A more complex rule of thumb is to use good water that contains minerals. Bottled (drinking or spring) water usually has the proper mineral content. Distilled or reverse osmosis water does not.