Abstract: An apparatus for controlling methane fermentation of organic materials including a main fermentor, sensors associated with the main fermentor for measuring physical-chemical measurements of organic material in the main fermentor, a computer for processing the measurements by using a fermentation model. An additional computer transforms the data of fermentation model into data which affects the operation of the main fermentor. A device is also provided to enable small-scale experimentation in order to adjust the characteristic parameters of the fermentation model incorporated in the computer. The installation allows to maintain the fermentor in optimum biological conditions with a minimum of measurements.