The invention concerns a solid state fermenter in particular for large volumes as well as a procedure for solid state fermentation. The task of the present invention was the development of a solid state fermenter for large volumes and of a procedure for solid state fermentation, that allows an economic application of the solid state fermentation for little competitive micro-organisms in large fermenters. The solid state fermenter according to the invention is characterized by representing a module fermenter, where at least two module bases, that are permeable for air and water, are arranged on top of each other, which are connected with the wall of the vessel in such a manner, that neither air nor water can pass laterally, the existence of a cultivation substrate for the micro-organisms, which have to be cultivated, on the module bases, a cooling device below every module base and the fermenter being closed with a lid.