Fermentation graphs of a Saccharomyces cerevisiae cultivation. The graph shows O2, CO2, pO2 and stirrer speed of a process where pO2 was controlled via agitation. Also shown are the calculated parameters COQ and OCQ. The curves obtained are highly reproducible and indicate differences in the respiratory activity of the fermented organism. The red shaded box shows OCQ (grey) and averaged OCQ (black) above 3 min which drastically reduces the noise from measurements.