Water for extraction : composition, recommendations, and treatment

Water is an essential ingredient for coffee extraction, typically making up more than 90% of the final beverage. This chapter introduces the basic characteristics of water and the most common dissolved contents. The concepts of water hardness and alkalinity are explained while discerning between technical and sensory aspects with regards to coffee extraction. The existing recommendations on the optimum water composition are discussed as well as the potential off-flavors that can arise from nonideal composition. As a link between a given water composition and a targeted recommendation the most common water treatment methods are systematically characterized. The chapter concludes with practical examples on the impact of different water compositions in a cupping experiment and espresso extraction.