This revised SCA Water Quality Handbook, featuring the water chart and practical guide sets out to establish a solid scientific framework for a unified and transparent consensus on how we measure, aim and treat water for coffee. The fulcrum of this discussion revolves particularly around the two core parameters of alkalinity and total hardness. In particular, we will explore the suitability of different water treatments by deepening our understanding around total hardness as a crucially important parameter in the proper extraction of coffee. Drawing on recent published research and experiments conducted by the Coffee Excellence Center at Zurich University of Applied Sciences (ZHAW), this handbook serves to promote a spirited exchange of ideas about the water we use for brewing within the specialty coffee community. An updated practical guide and Glossary of terms also offers the user a toolbox of concepts and methods with the aim of making coffee better in the domestic or commercial environment.