Abstract: A device for the treatment of biomass, including: a biomass cavity; a first magnet arrangement having at least one first permanent magnet; and a second magnet arrangement having at least one second permanent magnet; all first permanent magnets of the first magnet arrangement being situated on the outer periphery of the cavity, with their north poles oriented toward the cavity and their south poles oriented away from the cavity; and all second permanent magnets of the second magnet arrangement being situated on the outer periphery of the cavity with their south poles oriented toward the cavity and their north poles oriented away from the cavity; so that the flux lines from a north pole of a first permanent magnet to a south pole of at least one second permanent magnet run in the cavity, the first and second magnet arrangement each comprise a plurality of first or, second permanent magnets.