A process for clarifying raw juice in which the proportion of solids in the retentate circuit (2, 3, 4) of an ultrafiltration or microfiltration device (1) is sharply increased during the starting time (FIG. 1). With increasing proportion of solids, the filtration yield falls off sharply and then increases again to a value which is higher than the starting value. On reaching the maximum possible filtration yield value, the proportion of solids and thereby also the filtration yield is maintained constant by regulating the amount of retentate outflow or the amount of fresh juice to be fed in. In this way the filtration yield can be significantly improved.