Low-cost and portable refractive optoelectronic device for measuring wine fermentation kinetics

The fermentation process that gradually turns must into wine influences to a large extent the characteristics of the final product. The quality of wines would largely benefit from exhaustive testing procedures during the whole fermentation. This work demonstrates the potential of refractive techniques to successfully record the fermentation kinetics by means of a low-cost and portable optoelectronic system, liable to be advanced into a fully automated prototype thanks to an observed trend change in refractive index. The system core features a laser diode and a PSD (position sensitive detector), achieving a sensitivity of 4.6 × 10−4 RIU (refractive index unit) on discrete samples, a similar figure to those reported by instruments utilized by enologists. The prototype has been validated with model solutions as a prior step toward the monitorization of the must fermentation in a laboratory fermenter. Consequently, it represents an alternative method to traditional areometry for recording the fermentation evolution.