NOVELTY - The method comprises: providing (12) a biogas plant with two spatially separated container spaces; adding an activator to provide a biomass for a biochemical treatment; adding (34) the biomass into a first container space; creating (36) a first reaction condition for the formation of acetic acid, at a temperature of 49-51 degrees C under aerobic conditions, from the added biomass in the first container space; transferring (54) the biomass and the formed acetic acid into a second container space; and creating (64) a second reaction condition for the formation of methane in the second container space.    USE - The method is useful for producing biogas from biomass (claimed).    ADVANTAGE - The method allows simple, efficient and economical production of the biogas from the biomass with less effort.    DETAILED DESCRIPTION - The method comprises: providing (12) a biogas plant with two spatially separated container spaces; adding an activator to provide a biomass for a biochemical treatment; adding (34) the biomass into a first container space; creating (36) a first reaction condition for the formation of acetic acid, at a temperature of 49-51 degrees C under aerobic conditions, from the added biomass in the first container space; transferring (54) the biomass and the formed acetic acid into a second container space; creating (64) a second reaction condition for the formation of methane at a temperature of 37-39 degrees C in the second container space; and adjusting a pH value of the acetic acid to 3-3.5. An acetic acid formation activator is added to create the first condition in the first container space, and includes a germinated seed material, an enzyme, living yeast and living acetic acid bacteria. Methane-formed bacteria are added to create the second condition in the second container space. The method further comprises: measuring the pH value of the biomass in the second container space; transferring the biomass and the formed acetic acid from the first container space into the second container space in dependence of the measured pH value (7.2) in the second container space; providing a third spatially separated container space from the first and second container spaces; transferring the biomass from the second container space into the third container space; creating a third reaction condition for the formation of further methane at a temperature of 31-33 degrees C in the third container space; measuring the pH value of the biomass in third container space; and transferring the further biomass from the second container space into the third container space in dependence of the measured pH value (7.5) in the third container space.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of a method for producing biogas from biomass.    Providing a biogas plant with two spatially separated container spaces (12)    Adding a biomass into a first container space (34)    Creating a first reaction condition for the formation of acetic acid (36)    Transferring the biomass and the formed acetic acid into a second container space (54)    Creating a second reaction condition for the formation of methane. (64)