This document specifies a method for the determination of the speed and effectiveness of the neutralizing potential of calcium carbonate@ calcium magnesium carbonate and calcium magnesium silicate liming materials by potentiometric titration with hydrochloric acid. For liming materials coarser than 1 mm@ it is essential to prepare the sample of a liming material by following exactly the description of Annex A. This method is applicable only to liming materials with a maximum particle size of 6@3 mm. The type of liming material can be identified according to EN 14069 and the particle size can be determined according to EN 12948.