A retorting system configured for a batch-wise processing of a substance, comprising a retort, an oven, ductwork and a control system, wherein: a) the retorting system is configured for accommodating the retort in the oven; b) the ductwork comprises an inlet and an outlet duct; c) the retort comprises at least one retort outlet for extracting a product fluidum during the processing, and an opening for loading the retort with the substance prior to the processing and for discharging the processed substance after the processing; the retort outlet situated at the bottom of the retort; c1) the inlet and the outlet duct are both situated below the retort, d) the retort is coupled to the inlet and the outlet duct of the ductwork, the retort outlet being coupled to the outlet duct; e) the retort comprises at least one flow deflector, internal to the retort, for controlling a direction of a heat carrier fluidum from the inlet duct upwards through the retort via the at least one flow deflector, deflected at the top of the retort and then downwards through the retort to the outlet duct; f) the control system is arranged to control - a flow of heat carrier fluidum in through the inlet duct, through the retort via the at least one flow deflector and out through the outlet duct for direct heat transfer to the substance inside the retort, and - an indirect heat transfer to heat the substance in the retort from outside the retort across the retort wall, wherein the indirect heat transfer is applied over the surface of the wall of the retort, to controllably initiate, in operation, a reaction at a position remote from the retort outlet by controlling the flow and/or temperature of the heat carrier fluidum or by concentration of the indirect heat at or near said position, or by a combination of the two heat inputs and to progress the reaction downwards towards the retort outlet at the bottom of the retort, wherein the retorting system comprises a collecting element at the bottom of the outlet duct for collecting a liquid product fluidum formed in the retort and passed through the retort outlet. a) the retorting system is configured for accommodating the retort in the oven; b) the ductwork comprises an inlet and an outlet duct; c) the retort comprises at least one retort outlet for extracting a product fluidum during the processing, and an opening for loading the retort with the substance prior to the processing and for discharging the processed substance after the processing; the retort outlet situated at the bottom of the retort; c1) the inlet and the outlet duct are both situated below the retort, d) the retort is coupled to the inlet and the outlet duct of the ductwork, the retort outlet being coupled to the outlet duct; e) the retort comprises at least one flow deflector, internal to the retort, for controlling a direction of a heat carrier fluidum from the inlet duct upwards through the retort via the at least one flow deflector, deflected at the top of the retort and then downwards through the retort to the outlet duct; f) the control system is arranged to control - a flow of heat carrier fluidum in through the inlet duct, through the retort via the at least one flow deflector and out through the outlet duct for direct heat transfer to the substance inside the retort, and - an indirect heat transfer to heat the substance in the retort from outside the retort across the retort wall, wherein the indirect heat transfer is applied over the surface of the wall of the retort, to controllably initiate, in operation, a reaction at a position remote from the retort outlet by controlling the flow and/or temperature of the heat carrier fluidum or by concentration of the indirect heat at or near said position, or by a combination of the two heat inputs and to progress the reaction downwards towards the retort outlet at the bottom of the retort, wherein the retorting system comprises a collecting element at the bottom of the outlet duct for collecting a liquid product fluidum formed in the retort and passed through the retort outlet. - a flow of heat carrier fluidum in through the inlet duct, through the retort via the at least one flow deflector and out through the outlet duct for direct heat transfer to the substance inside the retort, and - an indirect heat transfer to heat the substance in the retort from outside the retort across the retort wall, wherein the indirect heat transfer is applied over the surface of the wall of the retort, to controllably initiate, in operation, a reaction at a position remote from the retort outlet by controlling the flow and/or temperature of the heat carrier fluidum or by concentration of the indirect heat at or near said position, or by a combination of the two heat inputs and to progress the reaction downwards towards the retort outlet at the bottom of the retort, wherein the retorting system comprises a collecting element at the bottom of the outlet duct for collecting a liquid product fluidum formed in the retort and passed through the retort outlet.