A method of calibrating a centrifugal separator having a rotatable bowl with a disc stack, wherein the centrifugal separator receives an intake of unseparated liquid food that passes through the disc stack for separation into a heavy product phase, a light product phase and a sediment phase by centrifugal separation, the method comprising: retrieving stored data representing a first correlation, the first correlation being a correlation between different amounts of discharges of the sediment and rotational speed reductions of the rotatable bowl due to the discharges; generating a first trigger signal to discharge a first amount of sediment; measuring a first rotational speed reduction of the rotatable bowl that corresponds to the discharge of the first amount of sediment; obtaining a first value corresponding to the first amount of sediment based on the first rotational speed reduction and the stored data representing the first correlation; generating a second trigger signal to discharge a second amount of sediment; measuring a second rotational speed reduction of the rotatable bowl that corresponds to the discharge of the second amount of sediment; obtaining a second value corresponding to the second amount of sediment based on the second rotational speed reduction and the stored data representing the first correlation; determining data representing a second correlation, the second correlation being a correlation between the different amounts of discharges of the sediment and trigger signals, based on the first and second trigger signals (S1, S2) and the first and second values (D1, D2) corresponding to the first and second amounts of sediment; and obtaining a third trigger signal corresponding to a desired amount of sediment to be discharged, based on the determined data representing the second correlation. retrieving stored data representing a first correlation, the first correlation being a correlation between different amounts of discharges of the sediment and rotational speed reductions of the rotatable bowl due to the discharges; generating a first trigger signal to discharge a first amount of sediment; measuring a first rotational speed reduction of the rotatable bowl that corresponds to the discharge of the first amount of sediment; obtaining a first value corresponding to the first amount of sediment based on the first rotational speed reduction and the stored data representing the first correlation; generating a second trigger signal to discharge a second amount of sediment; measuring a second rotational speed reduction of the rotatable bowl that corresponds to the discharge of the second amount of sediment; obtaining a second value corresponding to the second amount of sediment based on the second rotational speed reduction and the stored data representing the first correlation; determining data representing a second correlation, the second correlation being a correlation between the different amounts of discharges of the sediment and trigger signals, based on the first and second trigger signals (S1, S2) and the first and second values (D1, D2) corresponding to the first and second amounts of sediment; and obtaining a third trigger signal corresponding to a desired amount of sediment to be discharged, based on the determined data representing the second correlation.