Home » Journal Entries » The Influences of Different Winemaking Techniques on the Mouthfeel of Shiraz Grapes

The Influences of Different Winemaking Techniques on the Mouthfeel of Shiraz Grapes

A.P. Nel1,2, L. Louw3, M.G. Lambrechts1,3, P. van Rensburg1,3*

The objective of this study was to determine the effect of ripeness and of different tannin extraction
methods on the sensory properties of wine, with a specific focus on mouthfeel properties. Quantitative
descriptive analysis (QDA) was performed to evaluate the sensory properties of 20 young Shiraz wines in
two phases. In Phase 1, wines from a cool area were evaluated and, in Phase 2, wines from a warm area
were evaluated. Clear differences were found between the wines from the two regions. Wines from the
cooler region were generally associated with higher levels of total non-flavonoids and total anthocyanins,
and more intense numbing and puckering sensations. In contrast, the wines from the warmer region as
a group were associated with a more drying and grippy mouthfeel, as well as less total anthocyanins and
total non-flavonoids. In the set of wines from the cooler region, the effect of ripeness was more pronounced
than in the set of wines from the warmer region. In both cases, riper grapes resulted in a coarser surface
smoothness, a more numbing sensation, a bitter aftertaste and less adhesive mouthfeel. The wines from
the cooler region that were harvested at a riper stage were associated with many of the anthocyanins/
anthocyanin derivatives and were negatively associated with hydroxycinnamate, procyanidin B1 and
delphinidin-3-glucoside-p-coumaric acid. In the warmer area, the riper grapes were again associated with
anthocyanins/anthocyanin derivatives, but this time were strongly associated with procyanidin B2, caffeic
acid, p-coumaric acid, catechin, coutaric acid and total non-flavonoids. The effect of tannin extraction
method on the sensory properties of the wines from the warmer region was more pronounced than in the
wines from the cooler region. Unfortunately, the differentiation between treatments was not consistent from
one ripeness level to the next. However, it appeared that the cold soak treatment differed the least from the
control, regardless of region or ripeness, whereas the post-maceration treatment differed the most based
on mouthfeel and phenolic composition. Although some mouthfeel attributes and phenolic compounds
were consistently associated with region and ripeness, it is not clear if mouthfeel can be manipulated
consistently by tannin extraction methods.

Sensory properties, mouthfeel, Shiraz, tannin extraction methods

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