In the cyclic preparation of a length of curds by draining a mixture of whey and curds in an upright column, formed by a permeable casing (2), the preparation cycle consists of at least three parts: a thickening phase and an extrusion phase from the column and a lateral discharge phase of the length of curds. The mixture is supplied to one end of the casing (2) and a length of the thickened mass of curds is removed periodically at the other end of the casing (2). The whey/curds column inside the casing (2) is moved forwards at slow speed in the longitudinal direction of the casing (2) during the thickening phase of the preparation cycle, the thickening phase and the extrusion phase taking place at the same time. The discharge phase of the cycle takes place when the column is stationary, within a time span which is less than 20% of the thickening phase and extru­sion phase.