Anaerobic digestion apparatus comprises a first chamber for retaining organic matter before and/or during anaerobic digestion and a second chamber for retaining organic matter during anaerobic digestion. The anaerobic digestion apparatus is configured to refrigerate or heat the first chamber to suppress methanogenesis in the first chamber. The anaerobic digestion apparatus comprises a controller programmed to regulate the anaerobic digestion process and to thereby reduce system perturbations. The flow of organic matter to the second chamber where methanogenesis is regulated. There is disclosed an inoculum for anaerobic digestion comprising Acetobacterium woodii and Methanosaeta concilii.