Due to the large energy potential in terms of biofuels production, in the near future the construction of new biogas plants is expected in Poland. However, before any investment in biogas market, it is necessary to conduct performance tests of methane production from the used substrates and to proceed simulation of the initial start‐up on a laboratory scale. The aim of the study was to simulate the start‐up of agricultural biogas plants on a laboratory scale using pig slurry and maize silage. In this simulation, made in laboratory scale, we have created the same conditions of running like for real scale biogas installation. The research tests shown good usefulness of advanced CSTR reactors to optimize the running of biogas installations on a real scale.