This GSO Standard specifies two methods for the determination of titratable acidity of fruit and vegetable products: - a potentiometric reference method; - a routine method using a coloured indicator. NOTE: The determination of the titratable acidity is of no value in the case of products to which sulphur dioxide has been added. In the case of some coloured products, it may be difficult to determine the end point of the titration in the latter method and the former method should preferably be used.