Abstract: A process for adjusting filling level in a gasifier for carbonaceous material in the form of a floating bed reactor in which biomass and/or coke (K) is transformed into a product gas includes providing a substantially conical, downwardly tapering floating bed reactor comprising an upper reactor ceiling a lower inlet opening into which biomass and/or coke (K) are introduced into the floating bed reactor from below and a gaseous gasification agent (V) is introduced upwardly, so that a fixed bed, which is elevated from the location of the inlet opening and held in suspension, forms within the conical reactor, wherein the flow rate of the gaseous gasification agent (V) together with the biomass and/or the coke (K) is adapted in such a way that a stable bed forms in the reactor.