A method for controlling the fuel filling level of a biomass boiler with a combustion chamber and a controllable fuel feed in the form of a screw conveyor with an adjustable feed rate, for feeding the fuel onto a combustion grate in the combustion chamber, a position indicator being provided in the combustion chamber, characterized in that the method comprises the following steps: a. provided that the position indicator does not indicate an exceeding of a predetermined filling level, activating the screw conveyor at a predetermined feed rate PA for a predetermined feed time ZA; i. repeatedly increasing the feed rate step by step by a value PC to the value PE and waiting for the time ZA until the position indicator indicates the exceeding of a predetermined filling level; b. as soon as the position indicator indicates the exceeding of the predetermined filling level, storing the current feed rate PE as stored feed rate PF and reducing the feed rate to the value PF*PD, wherein PD is a predetermined reduction factor, for a predetermined time ZC; i. repeatedly reducing the stored value PF step by step by the value PC and reducing the feed rate to the value PF*PD until the position indicator does not indicate an exceeding of the predetermined filling level; c. as soon as the position indicator does not indicate an exceeding of the predetermined level, waiting for a dead time ZE, during which the feed rate remains unchanged; i. after expiry of the dead time, increasing the feed rate to the last stored value PF provided that the position indicator does not indicate an exceeding of the predetermined filling level. a. provided that the position indicator does not indicate an exceeding of a predetermined filling level, activating the screw conveyor at a predetermined feed rate PA for a predetermined feed time ZA; i. repeatedly increasing the feed rate step by step by a value PC to the value PE and waiting for the time ZA until the position indicator indicates the exceeding of a predetermined filling level; i. repeatedly increasing the feed rate step by step by a value PC to the value PE and waiting for the time ZA until the position indicator indicates the exceeding of a predetermined filling level; b. as soon as the position indicator indicates the exceeding of the predetermined filling level, storing the current feed rate PE as stored feed rate PF and reducing the feed rate to the value PF*PD, wherein PD is a predetermined reduction factor, for a predetermined time ZC; i. repeatedly reducing the stored value PF step by step by the value PC and reducing the feed rate to the value PF*PD until the position indicator does not indicate an exceeding of the predetermined filling level; i. repeatedly reducing the stored value PF step by step by the value PC and reducing the feed rate to the value PF*PD until the position indicator does not indicate an exceeding of the predetermined filling level; c. as soon as the position indicator does not indicate an exceeding of the predetermined level, waiting for a dead time ZE, during which the feed rate remains unchanged; i. after expiry of the dead time, increasing the feed rate to the last stored value PF provided that the position indicator does not indicate an exceeding of the predetermined filling level. i. after expiry of the dead time, increasing the feed rate to the last stored value PF provided that the position indicator does not indicate an exceeding of the predetermined filling level.