Water, noun: As a brewed drink, coffee is 98% water. Consequently, its quality is important. The most important influence is its hardness (you can find this at the water works), which, in Germany, is indicated in “degrees of German hardness”, °dH. All coffees are good in range 2 (8-14°dH). However, in general, soft water is preferable to hard water. There are also coffees that are marked as being for hard water (20°dH and higher) and soft water (0-6°dH).