Water dilution calculator
Blending tap water with distilled or RO drops every ion proportionally — the fastest way to tame alkaline water. Enter your report and slide the percentage.
How it works
Each ion blends linearly: diluted = source × (1 − p) + dilution water × p. Alkalinity and residual alkalinity are recomputed from the blended ions rather than averaged — the one thing that does not blend linearly is pH itself, which is why this tool reports alkalinity instead.
FAQ
Why dilute brewing water at all?
Dilution is the simplest way to reduce alkalinity and mineral excess at the same time — every ion drops proportionally. Brewers with hard, alkaline tap water often cut it 30–70% with RO and rebuild the ions they actually want.
RO or distilled — does the choice matter?
Barely. Distilled is truly zero; RO retains a few ppm of everything. At typical dilution rates the difference is within measurement error of your water report.
How much should I dilute?
Work backward from alkalinity: if your water is 200 ppm as CaCO₃ and your pale beer wants under 50, you need roughly 75% dilution — or less dilution plus acid. The full calculator solves that trade-off with mash pH in the loop.
Does dilution change my water’s pH?
Almost not at all — pH is logarithmic and buffered, so blending waters doesn’t blend pH linearly. What reliably drops is alkalinity, which is what actually matters for the mash.
Per-ion linear blending with Kolbach residual alkalinity (1953); RO profile uses typical published values. The same dilution engine drives the full calculator.