A combine harvester includes at least one device for separating a crop stream into at least two crop streams that each contains different compositions of crop components. The device delivers at least one crop stream to at least one of a number of grain pans assigned to the device. The grain pan transfers the crop stream to a cleaning mechanism. At least one roller pair extending transversely to a longitudinal axis of the combine harvester separates the crop stream. A first roller and a second roller of the roller pair have a relative speed with respect to one another.