Filter or drip coffee is made by hot water passing through ground coffee. Hot water is filtered solely under the pull of gravity. When water comes into contact with ground coffee, the flavours, colour and aroma from the coffee are extracted and dissolved in the water. This is known as extraction.
It is important to use ground coffee suitable for filter machines, and not espresso coffee, because it has been specially prepared for the purpose. There are many excellent brands to choose from, which are available from your local coffee specialist or supermarket.