WINE SWIRLING: A FIRST STEP TOWARDS THE UNLOCKING OF THE WINE’STASTER GESTURE

Abstract

Right after the pouring of wine in a glass, a myriad of volatile organic compounds, including ethanol, overwhelm the glass headspace, thus causing the so-called wine’s bouquet [1]. Otherwise, it is worth noting that during wine tasting, most people automatically swirl their glass to enhance the release of aromas in the glass headspace [1]. About a decade ago, Swiss researchers revealed the complex fluid mechanics underlying wine swirling [2]. However, despite mechanically repeated throughout wine tasting, the consequences of glass swirling on the chemical space found in the headspace of wine glasses are still barely known. A preliminary study was thus conducted to characterize the dynamic parameters of the wine’s taster gesture. From a kinematic point of view, wine swirling, on a flat support, follows an orbital motion described by its radius of gyration and its angular speed. A video processing program was developed to de- cipher the basic statistical parameters of this orbital motion done by a panel of 85 participants swirling INAO glasses filled with increasing levels of a water/ethanol mixture. Based on these statistical data, a homemade 3D-printed orbital shaking device was designed to replicate a standardized and repeatable glass swirling motion. Actually, In champagne and sparkling wine tasting, from the service of wine into the glass, gas-phase CO₂ was found to massively invade the glass headspace [3,4]. Therefore, the idea has emerged that gas-phase CO₂ could be considered as an ideal tracker to better understand the conse- quences of wine swirling on the chemical headspace inhaled by wine tasters. A spectrometer initially developed to monitor gas-phase CO₂ under static conditions was thus upgraded for the monitoring of gas-phase CO₂ in the headspace of champagne glasses automatically swirled by the 3D-printed orbi- tal shaking device [5]. The first datasets recorded thanks to this setup show a sudden drop in the CO₂ concentration in the glass headspace, probably triggered by the liquid wave traveling along the glass wall following the action of swirling the glass.