Sensory impact of skin contact on white wines characterized by descriptive analysis, time–intensity analysis and temporal dominance of sensations analysis

• Wines were evaluated by three complementary sensory techniques: DA, TI and TDS.
• Varying skin contact changed significantly odor attributes and in-mouth modalities.
• Temporal methods helped to understand sensory changes due to altered phenol extraction.

In white wine fermentation, extended skin contact of crushed grapes is frequently used to increase the varietal aromas of white Riesling and Gewürztraminer wines. At the same time, phenolic compounds are extracted which can yield significant increases in bitterness and/or astringency. Descriptive analysis (DA), time–intensity analysis (TI) and temporal dominance of sensation (TDS) analysis were used to evaluate the changes in flavor of Riesling and Gewürztraminer wines made with varying skin contact times. DA showed that Riesling wines differed only in bitterness and color. In contrast, Gewürztraminer wines varied significantly in bitterness, sweetness, sourness, and astringency as well as for several aroma notes and color. 2009 and 2010 Gewürztraminer wines increased in intensity of honey/caramel, floral, and lemon aromas as well as yellow color, whereas peach/apricot was only significant in 2009 and apple and green grass/green banana only in 2010. Regarding the temporal properties of orally perceived modalities, bitterness TI curves recorded from Gewürztraminer differed significantly in maximum intensity and area under the curve, while Riesling showed no significant differences in any TI parameter. Increasing skin contact altered the dominance of orally perceived attributes. Fermenting the grapes completely on their skins produced a wine, which was significantly more bitter than all other wines according to TI and DA. However TDS analysis showed that the dominating sensation in this wine was not the bitter taste but the astringent mouth feel. TDS revealed further subtle differences caused by botrytized grape material, altering sourness and astringent perception.