Brewing water chemistry, without the spreadsheet
brewwtr is a free brewing water calculator: enter your water report, pick a target profile, and get exact mineral and acid additions with a live mash pH prediction — on your phone, at the brew station.
Free forever. No account, no ads — your batches stay on your device.
Mash pH that solves itself
A charge-conservation pH model predicts your mash pH from grist and water, then goal-seeks the acid dose to land your target — lactic, phosphoric, or any of nine acids, solids included. No iterating by hand.
Chemistry you can audit
Every formula comes from published science — carbonate equilibrium, Kolbach residual alkalinity, Morey color — validated against Kai Troester's bench measurements and cross-checked against the classic spreadsheets. 31 malts ship with measured DI pH and buffering data.
Built for brew day
Everything recalculates as you type. A brew-day summary shows exactly what to weigh and add — mash and sparge separated — printable, copyable, and readable at arm's length with wet hands.
From water report to brew day in four steps
- Enter your water. Type the six ions from your water report — or quick-set distilled/RO if you build from scratch. Alkalinity, hardness, and residual alkalinity compute instantly.
- Pick a target. Historical city profiles like Burton-on-Trent and Pilsen, style-based targets, or your own custom numbers.
- Add your grain bill. 36 malts with typical colors — 31 with measured pH data — and your own DI pH overrides per lot.
- Hit the numbers. Auto-suggest minerals, watch the ion bars close in on target, and let the goal-seek dose your acid. The summary is ready to print.
The science, cited
brewwtr implements textbook carbonate chemistry and a proton-deficit mash pH model in the tradition of A.J. deLange and D.M. Riffe, parameterized with measured malt data from Kai Troester's 2009 experiments and deLange's published titration curves. Residual alkalinity follows Kolbach (1953); beer color uses the Morey equation; historical water profiles follow Palmer & Kaminski's Water (2013). The engine is open about where models disagree — and sides with the measurements.
Predictions are guidance, not gospel: measure your mash at room temperature and calibrate with the built-in pH meter offset.