AN ONLINE SENSOR FOR MONITORING OF ETHANOL IN BEER

A modification of previously known online sensors for continuous measurement of ethanol and other volatile compounds using a gas sensitive semiconductor detector, in combination with gas permeable membranes, is presented. The online sensor is provided with a continuous dilution system which dilutes the ethanol samples to a degree necessary to obtain accurate signals from the detector in concentration ranges appearing in beer and other brewery products. The instrument delivers a continuous voltage of 0–10 V, proportional to ethanol concentrations of 0–20% (w/v) with an analysis time of 10–15 min. Disturbances from carbon dioxide and sugars in the medium are small and negligible. Other volatile compounds are only of influence when their concentrations are comparable to that of ethanol.