The inline or online monitoring of fermentation processes is becoming increasingly important. In this context, industry is facing increasing demands for fast and accurate analytical methods to optimize cultivation conditions and reduce fermentation time. Product-specific analysis is carried out offline most of the time. However, such a procedure is labor-intensive and expensive. With offline measurements, it is also problematic that there is a time lag between the fermentation process and the analytical result. Especially in batch fermentations, overproduction can lead to by-products and degradation products. Therefore, timely, process-integrated online analysis is important in order to be able to control the fermentation process in a targeted manner. Our Gas and liquid analyzer Vario two. measures volatile substances with an interface to the bioreactor faster, more sensitively and more cost-effectively.