Chemical and Sensory Evaluation of Astringency in Washington State Red Wines

Astringency is one of the most important sensory attributes in red wine and is attributed to the presence of phenolic compounds. The objective of this study was to determine the relationship between tannin, anthocyanin, and small (SPP) and large (LPP) polymeric pigment concentrations in numerous Washington State red wines and to relate these values to perceived astringency. Three groups of wines were formed from a larger collection of wines based on tannin concentration: low (<400 mg/L CE), medium (400–800 mg/L CE), and high (>800 mg/L CE). Cabernet Sauvignon wines representing low, medium, and high tannin concentrations were selected and evaluated by 18 untrained panelists. Sensory results indicated that panelists gave significantly higher astringency ratings to wines high in tannin concentration compared with wines low in tannin concentration (p ≤ 0.05). In a second study, a trained panel evaluated Cabernet Sauvignon and Merlot wines representing combinations of low, medium, and high tannin, anthocyanin, SPP, and LPP concentrations. Results indicated that perceived astringency was significantly correlated with tannin, SPP, and LPP levels, while bitterness was significantly correlated with SPP, LPP, and tannin levels (p ≤ 0.05). These results indicated a relationship between polyphenolic compounds (tannins, SPP, and LPP) and the sensory attributes of astringency and bitterness.