Water Recipe Builder
See where your water falls against 9 named recipes. Pick a target. Get the exact DIY formula.
GH × KH × SCA
How well do you know your water?
How This Works
The Two-Bottle Method
Most DIY water recipes use two mineral concentrates. Bottle 1 adds General Hardness (GH) via magnesium sulfate (Epsom salt). Bottle 2 adds Carbonate Hardness (KH) via sodium bicarbonate (baking soda). Our concentrates are calibrated so 1 mL per liter = 1 ppm, making the math simple: a recipe calling for GH 76 needs 76 mL of Bottle 1 per liter of final water.
Why GH and KH Matter
GH (hardness) determines extraction power — how much flavor your water pulls from coffee. KH (alkalinity) acts as a buffer, controlling how much acidity survives into the cup. The ratio between them shapes the overall flavor profile: high GH:KH = bright and complex, low GH:KH = smooth and muted.
The SCA Standard
The Specialty Coffee Association publishes a target of 150 ppm TDS, 68 ppm GH, and 40 ppm KH (1.7:1 ratio). The shaded zone on the chart represents the broader acceptable range. Most well-regarded recipes cluster near or within this zone.
SCA Water Quality Standards (2019). Hendon, C. et al. "The Role of Dissolved Cations in Coffee Extraction" (Journal of Agricultural and Food Chemistry, 2014). Rao, S. "Everything But Espresso" (2010). Barista Hustle DIY Water Recipes (2017).