Sugar beets after washing and slicing into cossettes are heated in a counter-current mixer to about 70 °C in order to denature the cell walls. Thereby the cell walls are broken. From here the cossettes are pumped into an extractor (diffuser) where the sugar and other soluble cell substances are extracted from the cossettes to the water solution. Calcium salts are added and the pH value is kept below 6 in order faciltate the pressing of the pulp. Several types of appartuses have been developed, i.e. tower, drum and bed extractors. Today mainly tower extractors are in use.