One of the main applications is the testing of fermentable substrates prior to use in biogas systems to estimate the gas yield. Anaerobic degradation processes are conducted without oxygen. In order to be able to fill the gas room with inert gas above the sample at the start of the test, the measuring bottle is equipped with lateral connection hubs. These connection hubs are sealed with septa, so that carbon dioxide can be removed from the gas room following the anearobic degradation by adding a CO2 absorber. The resulting pressure difference is proportional to the CO2 concentration, the remaining overpressure is proportional to the methane concentration.

The degradation process can be tracked timewise with the operating mode "pressure". The use of special measuring bottles with lateral connection hubs and septa seals allows the interference-free addition of substrates and solutions. As the methane gas production running under anaerobic processes leads to a pressure increase, the measuring range limits may be exceeded. For such cases, it is possible to indicate a "warning pressure" or pressure limit value, so that the user can manipulate the system.