the basics
There are a few things to keep in mind when buying and producing coffee to drink.You should always purchase freshly roasted coffee - Coffee is a food, the fresher it is the better it is. Coffee which is too old becomes oily, it is the very oils that help to produce a perfect brew that can also help destroy it, coffee oils when they are old become putrid and spoil the coffee, leaving you with a rancid flavour.
Keep equipment clean - Equipment that is unclean can harbour coffee oils which if left in your brewing equipment will spoil any further extraction, it is best to clean your equipment directly after use.
Store your coffee - Coffee should be stored in an airtight container away from heat, moisture and light, all of these things affect the end result of your brew.
Ground coffee - Coffee should be ground correctly for your equipment, and incorrect grind will leave you with an under or over extracted brew. Try to grind your own coffee as you require it, if you do not have a grinder store ground coffee in a cool dark cupboard in an airtight container. Always try to make ground coffee purchases in the smallest amount possible.