Hard and Soft Tannins: Sensory Definition and Chemical Interpretation

Twelve 1998 Cabernet Sauvignon wines have been obtained from wineries (with minimal oak contact) to select those perceived to be “hard” and “soft”. Winemakers have been interviewed in an attempt to define how each makes the judgement. Although ‘hard” or “soft” are customarily defined by mouthfeel, the contribution of other wine sensory properties is not known. These factors could include color, the aroma and flavor of the wine. More subtle, yet important, we do not know how each individual integrates the perception of taste and mouthfeel. Ten winemakers participated in a “sorting” test in which they were asked to taste the 12 wines and group them on the basis of their perceived similarity. The wines were served in dark beakers, so no information from smell or color was available for this task. Each winemaker used his/her own criteria for the grouping. (For these tests, dark glasses were used to remove color cues). Students at UCD did the same similarity sorting tasks and then were trained for time-intensity (TI) studies in which the intensity of each attribute was rated continuously over time. For each wine, the trained judges took one sip of wine and initiated rating intensity; at a prompt they swallowed the wine, then 25 sec after the first sip, they took a second sip, while continuing to rate the intensity. The procedure of rating for two successive sips was used to include the carryover effects that occur under standard tasting conditions in which several sips are taken, without rinsing. Bitterness, astringency and sourness were evaluated in duplicate, using blue glasses and testing under red light.