Abstract: The invention relates to an installation for the recovery of methane gas from organic waste with a fermentation space, a gas collecting space and a post-fermentation space, as well as with at least one supply line into the fermentation space and one offtake for the excess, fermented liquid from the post-fermentation space, the spaces being heat-insulated and preferably embedded at least partially in the ground, and the post-fermentation space, which preferably is arranged above the fermentation space, being connected in the manner of communicating vessels with the fermentation space, preferably in one structural unit.