The relevant and complex role of ethanol in the sensory properties of model wines

In a context of increasing interest in the production of wine-based beverages with lower ethanol content, the present work explored the role of ethanol in the sensory properties of model wines (MW). Four sets of MWs (red and white) with alcohol contents ranging from 0.5 to 15 % (1st study) and from 12 to 15 % (2nd study), the non-volatile fraction of real wines and fixed aroma compositions were all prepared and characterised by sensory descriptive analysis. The results indicate that sensory effects were stronger in red MWs than in white MWs, and that alcohol levels below 10 % in reds and 7.5 % in whites cause the models to become unbalanced with excessive sourness. In whites, low-alcohol MWs also showed reduced levels of perceived bitterness, and only at high ethanol levels were body and alcoholic aroma more intense. In reds, the low alcohol MWs showed less positive aroma persistence (perceived retronasally) and less body; at 0.5 % ethanol the positive odour intensity (perceived orthonasally) was minimal and at higher ethanol levels, the models became sweeter and more alcoholic. Overall, although samples with similar alcoholic contents maintained some sensory similarity, there were relevant discontinuities caused a slight increase in ethanol (0,5 %) to have a dramatic sensory impact, with some sensory descriptors showing significant maxima or minima at these alcohol levels. In reds, sourness, alcohol and astringency perceptions were maximum at 13.5 % and 15 % and body at 13 % and 15 %; meanwhile, red fruit was minimum at 13 % and 15 %, peaking at 14.5 %. In whites, alcohol perception was also maximum at 13.5 % and 15 %, while sweetness was maximum at 13.5 % and 14.5 %. These results demonstrate that ethanol exerts profound effects on sensory properties, probably due to strong perceptual interactions with odour, taste and tactile properties.