Mash pH
Term from the Brauwerkstatt brewing glossary, category “Brewing water and pH”.
Explanation
pH of the mash 10–15 minutes after mashing in, measured at 20 °C (68 °F). Usually aim for 5.4–5.5. It affects efficiency, clarity and how smooth the hop bitterness tastes.
Work it out yourself
Brewing water calculator – Adjust your tap water to the beer style: the calculator tells you how much calcium chloride, gypsum and lactic acid you need.
Test your knowledge
What does the residual alkalinity of brewing water describe?
- How much chlorine the water contains
- How strongly the water raises the mash pH
- How warm the water is
Show answer
Correct: How strongly the water raises the mash pH. High residual alkalinity suits dark beers; for pale beers it is lowered with lactic acid or soft water.
Why add lactic acid to the brewing water or the mash?
- To dissolve the hops
- To lower the pH
- To make the beer taste sour
Show answer
Correct: To lower the pH. In small amounts you cannot taste lactic acid. It brings the mash pH into the right range.
Who developed the pH scale at the Carlsberg Laboratory in 1909?
- Carl von Linde
- Louis Pasteur
- Søren Sørensen
Show answer
Correct: Søren Sørensen. Homebrewers still use the same scale today to measure mash pH.
Frequently asked questions
Alkalinity target or beer colour, which should I use?
Both aim for the same result, a mash pH of about 5.4–5.5. The fixed alkalinity target is simple; beer colour takes calcium into account and often saves a little lactic acid. The measured mash pH is what counts.
Can you taste a few mg/l of residual alkalinity?
No. About 18 mg/l of residual alkalinity shifts mash pH by only about 0.03, which is below the accuracy of typical pH meters.