Acid Addition Calculator

Calculate how much lactic acid, phosphoric acid, or acid malt to add to lower your mash or sparge water pH to the target range.

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How It Works

Acid additions are the most common way to hit the target mash pH of 5.2-5.6. Lactic acid (88%) is the most popular choice — it is flavorless at typical dosages and widely available. Phosphoric acid is an alternative that does not add any flavor at all, making it preferred for very light beers. Acid malt (acidulated malt) is a Reinheitsgebot-compliant option that contains lactic acid developed during malting — use 1-5% of the grist. Start with half the calculated amount, stir well, wait 5 minutes, then measure pH before adding more. All pH calculations are estimates; real-world results vary with grain lots, water composition, and temperature.