Ultrasound based measurements of sugar and ethanol concentrations in hydroalcoholic solutions

Industrial automation is useful to reduce production costs and improve product quality. The wine industry has been increasingly adopting industrial automation seeking these objectives. In Chile, wineries have been lagging behind in embracing new technologies to control the fermentation process. In most cases, enologists decide control actions (cooling, heating, pumping over) based on off line periodic measurements. In this work we explore the applicability of ultrasound to measure the sugar and alcohol concentrations of hydroalcoholic solutions mimicking fermenting musts. Additionally, implementation issues such as the attenuation effect of bubbles and tank curvature are analyzed. We show that working at two sufficiently distinct frequencies, we can measure sugar and alcohol content simultaneously. Measurement resolution achieved for the wave time of travel translates to a better than 0.02% for both concentrations, depending on the container size.