A new approach for monitoring the alcoholic fermentation process based on acoustic emission analysis: A preliminary assessment

A preliminary study focused on the feasibility of using a new acoustic emission approach to be applied as pre-dictive monitoring tool of temperature variation during the alcoholic fermentation process is evaluated. The acoustic signal produced by the CO2 bubbling from a model fermenting liquid inoculated with saccharomyces cerevisiae was directly acquired by immersing a hydrophone into a 8 L lab scale experimental reactor. Fermenting liquid temperature was measured with a type-J thermocouple. Acoustic and temperature measurements were automatically and simultaneously performed each 30 min for a total fermentation period of about 4 days. Signals were digitalized and processed in dedicated software programmed on MATLAB (R) and LabVIEW (R). Frequency distribution analysis and maximum peak of the dominant frequency in function of the time were used as acoustic parameters to correlate with the temperature change behavior during fermentation in the reactor. The acoustic emission method proved to be a promising and sensitive tool to characterize and describe the alcoholic fermentation process.