WINETECH Technical Yearbook 2021

OENOLOGY RESEARCH | SEPTEMBER 2021

CAN TRELLIS AFFECT THE TASTE and mouthfeel of wines? Some of the most important classes of compounds affected by bunch microclimate are non-volatiles such as phenolics, sugars and organic acids. Some of these compounds go through chemical transformations during winemaking (e.g. sugars during fermentation), while the presence of others is dependent on the winemaking protocols (e.g. extraction of phenolics depending on the skin contact and pressing). The nature and concentration of the non-volatiles in the grape at harvest will influence the wine composition, but sometimes the differences at harvest are not proportional to the ones in the final product. In the previous article, we have presented results related to the aroma aspects of Chenin blanc wines made from various trellising systems; this time, the focus will be on the taste and mouthfeel (sensory) and non-volatile compounds (chemistry). TASTE AND MOUTHFEEL The same panels assessed the aroma, taste and mouthfeel of wines: in 2017 indus- try professionals and an analytical panel, while in 2018 only the analytical panel. In the case of taste and mouthfeel, the pan- ellists evaluated ‘body’ (full, medium and light), ‘complexity’ (complex and watery), ‘balance’ (balanced and unbalanced), ‘af-

tertaste’ (long, medium and short), and ‘af- tertaste driven by’ (flavour, acidity, alcohol and bitterness). The wines from similar trellis systems were perceived similarly by the two panels (2017). For both sets of results, there was a gradual change from one extreme (‘light body’, ‘short aftertaste’ and ‘unbalanced’ for Santorini) to a middle ground (‘balanced’, ‘medium aftertaste’, and ‘medium body’ for Smart- Dyson and Ballerina), then to the other end of the scale (‘full body’, ‘long aftertaste’ and ‘aftertaste driven by alcohol’ for T-frame). Lyre and Stok-by-paaltjie wines were placed between the ‘medium’ and ‘full’ categories. Smart-Dyson and Ballerina systems are variants of each other, which indicate that the canopy exposure and the resulting chemistry may be comparable to each other and different from others. A similar scenario could be considered for the horizontal open canopies of T-frame and Lyre. Moreover, the Santorini system treatment falls under shaded canopies, clearly separated further away from the open canopy wines, and described by characters such as ‘light body’, ‘watery’ and ‘aftertaste driven by acidity’. In 2018, the results (this time only from the analytical panel) were somewhat different from 2017. There was again a transition from ‘light’ to ‘medium’ to ‘full’;

Trellis effects on wine composition (PART 3: TASTE AND MOUTHFEEL)

ASTRID BUICA, VALERIA PANZERI & HILARIA IIPINGE: South African Grape and Wine Research Institute, Department of Viticulture and Oenology, Stellenbosch University, Stellenbosch KEYWORDS: Trellising systems, taste, mouthfeel.

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