This is a browser-based calculator for customizing brewing water for coffee.
It helps determine how much of each mineral solution you need to achieve ideal target water profiles.
- Define stock solution concentrations (MgSO₄·7H₂O, NaHCO₃, CaCl, KHCO₃)
- Set desired target ppm (mg/l) values for:
- Magnesium (Mg²⁺)
- Calcium (Ca²⁺)
- Sodium (Na⁺)
- Potassium (K⁺)
- Calculates:
- Required ml of each stock solution per liter of base water
- Total bicarbonate (HCO₃⁻)
- Total hardness and alkalinity (as CaCO₃)
- You can save custom profiles (presets) in your browser.
- Use Export / Import to back up or restore profiles.
- Presets and concentrations are stored using LocalStorage.
⚠️ Clearing cookies or site data will remove saved settings. Use export to preserve your data!
You can use this tool online by hosting it with:
Or simply open the HTML file in your browser.
index.html– the calculator UI and logic (standalone)presets.json– optional backup format for importing/exporting recipes
Pull requests and feature suggestions are welcome!
You can also fork and modify the calculator for your own needs.
Enjoy your perfect brew! ☕