TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The filling level measuring device comprises at least one sensor, by means of which the actual filling level of the substrate in the fermenter container is detected and is fed as height-actual value signal of the control device. The immersibility of the collar in the substrate is determined at least from this height-actual value signal and the predetermined known value for input depth of the collar in the fermenter container-interior. The control device with a measured low filling level, at which the collar is not immersed in the substrate, actuates at least one conveyor and/or pumping device (36), until at least one sensor provides the height-actual value signal corresponding to a filling level set point, and/or until the filling level of the substrate is achieved in the fermenter container, in which the collar is immersed in the substrate. At least one conveying and/or pumping device is formed by at least one vacuum pump system, which pumps the substrate to be fermented from the fermenter container. The vacuum pump system is switched off for raising the filling level by the control device for a defined time period. At least one conveyor and/or pumping device is formed through at least one pumping device for supplying the substrate to be fermented into the fermenter container. The pumping device pumps the liquid substrate from an upstream and/or downstream container into the fermenter container for increasing the filling level, which is controlled by the control device. The service opening is a part of the pedestal plate, from which the collar annularly enclosing the service opening projects downwards. The collar is formed by a separate component, which is connected to the pedestal plate, preferably positively and/or cohesively connected. The collar is an integral part of the pedestal plate and is integrally connected to the same material, preferably through straps bent by the pedestal plate. A container wall, preferably a container side wall and/or a film roof of the fermenter container are connected to the pedestal plate. The pedestal plate comprises at least one pedestal plate peripheral edge portion connected to the container wall, which rests in a gastight system connection to the container side wall and/or on the container top wall, preferably by means of a screw connection. The pedestal plate comprises a film roof terminal region, on which the film roof, preferably a film roof-edge area is connected in a gastight manner. The pedestal plate and a clamping bar are detachably connectable, preferably clamped with the clamping region by means of a clamping connection in a gas tight manner between the clamping range, preferably a rim flange. The pedestal plate is supported from below by means of a support device, preferably with a support truss, where the support device is connected and fixed on the wall side of the fermenter container interior wall area. The covering device closing the service opening in a gastight manner is formed by at least one lid, and/or by a housing, which projects upwardly away from the service opening. The housing forms a holding space for at least one upper portion of the guide mast.