This method, which may form the basis of sugar beet purchasing contracts, measures the optical rotation of the plane of polarised light caused by the sucrose content of a half-normal digestion solution of beet brei. The polarimetric sucrose content is expressed in °Z of the International Sugar Scale. This method is applicable to freshly produced and/or frozen sugar beet brei for the polarimetric determination of sucrose. Cossettes have to be comminuted. For beet of average sugar content of 18.7 °Z the absolute difference between two results obtained under repeatability conditions should be not greater than 0.15 °Z. The absolute difference between two results obtained under reproducibility conditions on such beet should be not greater than 0.40 °Z. For beet of average sugar content of 16.8 °Z, the absolute difference between two results obtained under repeatability conditions should be not greater than 0.30 °Z. The absolute difference between two results obtained under reproducibility conditions on such beet should be not greater than 0.50 °Z.