The Optothermal Approach to a Real Time Monitoring of Glucose Content During Fermentation by Brewers' Yeast

During production of both normal and low-alcohol beers, sugar is fermented to ethanol, carbon dioxide and several flavour products. Tight control of fermentation is necessary in order to keep production costs low, and to prevent formation of excessive ethanol in low-alcohol beer. Several types of control devices based on, e.g., determination of carbon dioxide, ethanol, and extract have been developed so far; the main disadvantage of these devices is their unsuitability for on-line applications. Here, the optothermal window was used in a laboratory experiment as a new sensor for real time monitoring fermentation of glucose by Saccharomyces cerevisiae, and the results were compared to those obtained by conventional techniques.