What is the ideal mash pH?

The ideal mash pH is 5.2-5.4 (measured at room temperature). This range optimises enzyme activity, extract efficiency, and produces a cleaner-tasting beer. Most water sources produce a mash pH above this range without adjustment.

Which acid should I use?

Lactic acid (88%) is most common in homebrewing — it is flavourless in small quantities. Phosphoric acid (10%) is flavour-neutral. Citric acid works but can add a slight citrus character. Acidulated malt is another option.

When should I measure mash pH?

Measure pH about 10-15 minutes into the mash after thorough mixing. Let the sample cool to room temperature before measuring, as pH meters are calibrated at room temperature. Hot samples will read 0.3-0.35 pH lower than actual.

Why is mash pH important?

Mash pH of 5.2-5.4 optimises enzyme activity for starch conversion, improves protein coagulation during the boil, and produces better hop utilisation. Beers brewed at correct mash pH have a cleaner, more defined flavour profile.

What acids are commonly used for pH adjustment?

Lactic acid (88%) and phosphoric acid (10%) are most common. Lactic acid is cheap and effective but can add a tart flavour if overused. Phosphoric acid is flavour-neutral. Acidulated malt (2% of grist) can lower pH by about 0.1 per percent used.

BrewCalcs

pH Adjustment Calculator

Calculate acid additions to hit your target mash pH.

Current Mash pH

Target pH

Mash Volume

Acid Type

How We Calculate This

pH Adjustment

This is a simplified estimate. Actual acid requirements depend on your water alkalinity, grain bill colour, and mash thickness. Start with half the calculated amount, stir well, wait 10 minutes, re-measure, and add more if needed.

Frequently Asked Questions

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Last updated: 2025-02-20

All calculations are estimates. Always verify values and adjust based on your equipment and ingredients.