Water quality for Espresso coffee

Espresso coffee extraction is the most common brewing method in Italy and it is becoming very popular in many other countries around the world. Water (including its ionic content) is an essential ingredient and its role in Espresso brewing must be taken into due consideration. It is well known that water treatment is necessary to remove possible off-flavours deriving from the disinfection performed at municipal waterworks as well as to prevent expensive professional Espresso coffee machine from scaling problems. However, there is little awareness of the direct effect of water composition on the quality of coffee beverages, particularly for Espresso coffee.In this paper, the state of the art is reviewed with emphasis of water/coffee components interaction during the brewing process. The role played by alkalinity and selected cations on sensory properties of Espresso coffee is discussed.