Until now, biogas technology has mainly concentrated on ”wet fermentation” of agricultural waste. Processability of materials with a high dry matter content solid waste were limited. The recently developed dry fermentation process allows methane yields from stackable organic matter with a high dry matter content, requiring no conversion into a pumpable liquid substrate. This method renders fermentation of biowaste possible with up to 50 % dry matter content. Biowaste is inoculated with substratum that has already been fermented. It is then filled into the tank and fermented under airtight conditions. Continuous inoculation with bacterial matter occurs per recirculation of percolation liquid, which is sprayed over the organic matter in the digester. During the fermentation process, no further mixing, pumping or stirring is necessary inside the digester, nor is further material added. Excessive percolation liquid is collected in a drainage system, temporarily stored in the percolation tank, and then re-sprayed over the biomass in the digester.