Mash pH Calculator
Free mash pH estimator with water chemistry and lactic acid correction
Water Profile
💡 Tip: Find these values on your water utility's website or in your water analysis report.
Grain Bill
Malt 1
Malt 2
5.76
Estimated Mash pH
4.55.2 – 5.67.0
5.70
Grain pH (DI water)
+40
Residual Alkalinity (ppm)
pH too high. To correct to ~5.4: • approx. 180 g acidulated malt (3.6% of grain bill) • or approx. 14.4–21.6 mL lactic acid (80%)
Lactic Acid Correction (80%)
14.4 – 21.6 ml
Add to mash water before doughing in. Always verify with a pH meter.
How the calculation works
This calculator uses the Troester model: Each malt type has a characteristic pH in distilled water (DI pH). The weighted average gives the base pH.
Your water's residual alkalinity (RA) shifts pH upward. High bicarbonate → higher pH. Calcium and magnesium counteract this and lower pH.
RA = HCO₃⁻/61 − Ca²⁺/(20·3.5) − Mg²⁺/(12·7) (in mEq/L)
- pH < 5.2: More dryness, thinner body
- pH 5.2–5.6: Ideal range
- pH > 5.6: Harsher bitterness, tannins