General Considerations

• Beers with a high pH are prone to infection by micro-organisms.
• Variation in beer pH can reflect inconsistency in fermentation.
• Problems may be encountered when beers of pH outside the normal range are fined.
• Problems may be encountered with flavour if the pH is outside the normal range.

Range of Values

• The acceptable range of pH for cask conditioned beers is 3·7 - 4·1 units (see also Topics 3 and 11).
• For a given brand the pH should not vary by more than ± 0·15 units

Operational Protocols

• The pH value of every beer should be taken at rack.
• Beers of very low (acid) pH should be checked for acidity produced by contaminating micro-organisms.

Measurement Protocols

• Beer should be degassed prior to measurement of pH.
• pH measurement to ± 0·1 units requires daily calibration of the pH meter and either a fixed temperature for measurement or automatic temperature compensation.