An apparatus for separating a volume of composite liquid into at least a first component and a second component in a separation bag, comprising: a rotor for spinning the separation bag around a rotation axis of the rotor; a fluid transfer system for causing a transfer of gas and at least a first fraction of a first component from the separation bag into a first component bag connected thereto; a memory for storing at least one rotor centrifugation speed allowing for the sedimentation of at least a first component and a second component of a volume of composite liquid contained in a separation bag; and a control unit programmed for: causing the rotor to rotate at the at least one rotor centrifugation speed so as to cause the sedimentation of at least a first and second component of a volume of composite liquid contained in a separation bag; causing the fluid transfer system to transfer gas and at least a fraction of the first component into a first component bag connected to the separation bag; and determining an actual volume of the at least one fraction of the first component transferred into a first component bag, between the first component starting pouring into the first component bag and the first component stopping flowing into the first component bag; wherein the rotor further comprises a separation compartment for containing the separation bag; wherein the fluid transfer system comprises a pumping means for pumping a hydraulic liquid, in increments of a determined discrete volume, into the separation compartment of the rotor for containing the separation bag, and wherein the control unit is further programmed for: counting the number of increments between the first component starting pouring into the first component bag and the first component stopping flowing into the first component bag; and determining the actual volume of the first fraction of the first component transferred into the first component bag from the counted number of increments and the determined volume corresponding to one increment. a rotor for spinning the separation bag around a rotation axis of the rotor; a fluid transfer system for causing a transfer of gas and at least a first fraction of a first component from the separation bag into a first component bag connected thereto; a memory for storing at least one rotor centrifugation speed allowing for the sedimentation of at least a first component and a second component of a volume of composite liquid contained in a separation bag; and a control unit programmed for: causing the rotor to rotate at the at least one rotor centrifugation speed so as to cause the sedimentation of at least a first and second component of a volume of composite liquid contained in a separation bag; causing the fluid transfer system to transfer gas and at least a fraction of the first component into a first component bag connected to the separation bag; and determining an actual volume of the at least one fraction of the first component transferred into a first component bag, between the first component starting pouring into the first component bag and the first component stopping flowing into the first component bag; causing the rotor to rotate at the at least one rotor centrifugation speed so as to cause the sedimentation of at least a first and second component of a volume of composite liquid contained in a separation bag; causing the fluid transfer system to transfer gas and at least a fraction of the first component into a first component bag connected to the separation bag; and determining an actual volume of the at least one fraction of the first component transferred into a first component bag, between the first component starting pouring into the first component bag and the first component stopping flowing into the first component bag; wherein the rotor further comprises a separation compartment for containing the separation bag; wherein the fluid transfer system comprises a pumping means for pumping a hydraulic liquid, in increments of a determined discrete volume, into the separation compartment of the rotor for containing the separation bag, and wherein the control unit is further programmed for: counting the number of increments between the first component starting pouring into the first component bag and the first component stopping flowing into the first component bag; and determining the actual volume of the first fraction of the first component transferred into the first component bag from the counted number of increments and the determined volume corresponding to one increment. counting the number of increments between the first component starting pouring into the first component bag and the first component stopping flowing into the first component bag; and determining the actual volume of the first fraction of the first component transferred into the first component bag from the counted number of increments and the determined volume corresponding to one increment.