AbstractAn improved apparatus for the semi‐micro, differential, potentiometric titration of starch and its components with iodine is described. The necessary experimental manipulations are given in detail. The factors affecting the measurement — the amount of dimethylsulphoxide present, the buffer concentration, the method of dissolving the starch, the defatting procedure used on the starch, and the temperature of measurement — are critically examined.The new technique results in values of iodine binding capacity for starches which are 5‐ 15% higher than previous measurements. The significance of this finding is discussed.