Effervescence description of No-Low alcohol wines at different temperatures and ethanol concentrations through image analysis

The increasing demand for no- or low-alcohol (NoLo) wines in the European beverage market has led to a rise in the availability of sparkling NoLo wines. However, comprehensive evaluations of their foamability and effer- vescence remain limited in the scientific literature. This study aims to provide a detailed assessment of the foamability of sparkling NoLo wines across various levels of dealcoholisation and temperatures. The Mosalux methodology was selected as the standard reference for this analysis. In the study, pure ethanol was incrementally added to a completely dealcoholised white-still wine, raising the ethanol concentration from 0 % to 12 %; at the same time, different wine temperatures ranging from 4 ◦C to 25 ◦C were tested. Additionally, artificial intelligence (AI) techniques based on image analysis were employed to assess foam collar persistence, count, and classify visible bubbles. Image acquisition was performed over several minutes to monitor foam behaviour, simulating a typical consumer evaluation continuously. An RGB camera captured images from above the experimental glass. The collected data were compared with the wine’s physical properties, using response surface methodology to describe the interaction between the liquid and gas phases. The results showed that ethanol reduction promoted the formation of stable and compact foam while reducing the average bubble diameter. The Mosalux data and wine physical properties were correlated with indices derived from the image analysis, which described bubble production potential and foam receding time. Maximum bubble production and bubble detection kinetics were found to be closely related not only to the wine’s viscosity and surface tension but also to the maximum height recorded with the Mosalux device. These findings suggest that alcohol reduction may enhance the overall visual appeal of sparkling NoLo wines while offering potential health benefits to consumers.