The sensory profile of astringency: application on Sangiovese wines

Abstract

One of the main sensory characteristics of red wine is astringency, which can be defined as drying, puckering and roughing of the oral cavity after the exposure to tannin-rich wines. Tannins are the main responsible for the intensity of the sensation as well for the qualitative aspects of astringency. However, the total intensity of the sensation is not sufficient to fully characterize red wine astringency. Thirty-three different subqualities (Gawel et al. 2001) had been generated to describe the complexity of this multi perceptual phenomenon, which includes both tastes, tactile, and flavor sensations. So, how to feel tannins during tasting? In this study, we used a sensory method that combine the training for astringency subqualities with touch-standards and the CATA questions, usually applied in consumer science, to evaluate the astringency subqualities of different typologies of Sangiovese: commercial and experimental wines. Sangiovese wine represents a good model for the study of astringency because it is generally characterized by a high content of low and high molecular weight proantocyanidins. Commercial wines differed for percentage of Sangiovese (80-100 %) grapes used in winemaking and for designation (Toscana TS, Chianti Classico CH, Chianti Riserva CR, Morellino di Scansano MS). The astringency profile of wines changed as the percentage of Sangiovese increased. Positive subqualities as velvet, soft, mouthcoat, and rich highly characterized the Sangiovese wine belonging to TS and CR designations. Moreover, the astringency subqualities related to blending or wood aging, represented the drivers of quality of commercial Sangiovese wines. Therefore, four experimental wines (SANG1, SANG2, SANG3, SANG4) made with 100 % Sangiovese grapes in different wineries of Tuscany were also used to evaluate the subqualities of Sangiovese wine. At 8th months post-harvest (8 mph) wines were mainly characterized by green (Cf=40-60 %), dry (35 %), and adhesive (35-55 %) terms, indicating that Sangiovese wine tannins were excessively astringent and acid (green), causing a drying and sticking sensation in mouth. In order to follow the evolution of the astringency profile of Sangiovese during time, wines have been evaluated at 14-16-20 mph. The SANG1 wine at 14 and 16 mph was characterized by hard tannins, which at 20 mph turned to corduroy and rich subqualities. The SANG2 wine at 14 and 16 mph was felt as satin and silk, while at 20 mph became rich, soft and mouthcoat. The SANG3 wine was silk, corduroy and persistent after 14-16 mph, and velvet and full-body after 20 mph. The SANG4 was velvet and grainy at 14th mph, rich and soft at 16th mph, and full-body, mouthcoat and persistent after 20 months. Finally, the astringency profile of Sangiovese wine has changed from an unripe astringency towards rich, full-body and mouthcoating sensations during aging. By means of the described sensory method, a detailed evaluation of the astringency profile of Sangiovese was made, and the evolution of the qualitative features of Sangiovese tannins during aging has been revealed for the first time.