Optimization of low-temperature vacuum distillation aimed at reducing the alcohol content in regional wines: impact on oenological, aromatic, and phenolic characteristics

Abstract

Recent market analyses indicate a sustained increase in consumer demand for low-alcohol wines, in line with the growing interest in health-oriented products [1]. Consequently, alcohol reduction has become a central topic in modern oenology, accompanied by the need to safeguard the characteristic properties of wine. Hence, the technologies currently authorized under European regulations frequently induce marked modifications in the organoleptic and sensory attributes of wine [2]. Concurrently, it is well recognized that ethanol content can enhance perceptions of pungency and bitterness while diminishing the perception of acidity [3]. In this context, the present study focused on the optimization of a vacuum distillation process for the reduction of alcohol content. Wines were produced from Raspato Nero grapes, an autochthonous cultivar of central Italy (Lazio region), harvested in early October 2024 at the ARSIAL experimental estate (Velletri, Rome). Distillation process was carried out at relatively low temperatures (30–32 °C) for different duration. Wines were analyzed for their alcoholic, oeno-chemical, phenolic, and aromatic profile. As expected, the distillation process resulted in a significant reduction of the alcoholic content, reaching approximately 6 % vol., while generally preserving the quality attributes. Specifically, the oeno-chemical parameters revealed an increase in acidity and a consequent modulation of pH, whereas total SO₂ levels and color hue remained comparable to the untreated control. Chromatographic analyses confirmed the overall preservation of the phenolic profile. On the other hand, the distillation process markedly affected the volatile fraction, leading to a reduction in fermentative esters. This outcome made a subsequent blending step necessary to restore the aromatic balance and mitigate the alterations introduced by distillation. As a result, the treated wine was blended with the original untreated matrix, yielding three wines with target alcohol levels of 8 %, 10 %, and 12 % vol. Overall, this strategy appears to be a promising approach for reducing alcohol content while preserving the quality traits of the wine.

References

 [1] J. C. Schmidtke, J. W. Blackman, S. O. Agboola; J. Food Sci., 76 (2011), R25–R41.

[2] M. Pickering; Crit. Rev. Food Sci. Nutr., 40 (2000), 275–301.

[3] A. de-la-Fuente-Blanco, M. Sáenz-Navajas, V. Ferreira; OENO One, 58 (2024), 1–18.