Weincampus Neustadt (Germany)

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AIM: Combined investigation of the influence of berry maturity, maceration time and wine maturation on the changes in polyphenols and sensory characteristics of Pinot noir and Cabernet Sauvignon. This comparative approach was chosen to assess the importance of the term “phenolic maturity” and its impact on polyphenols and sensory characteristics in the context of well-known effects observed during winemaking. Pinot noir and Cabernet Sauvignon were used due to the huge differences in the climatic growing conditions, in phenolic profiles in grapes and wines and their high international relevance.

METHODS: Pinot noir and Cabernet Sauvignon grapes of the vintage 2018 were harvested at three different stages of ripening. The grapes were macerated for 6 days or 13 days. Wines were analyzed immediately after pressing and three months after bottling to investigate the influence of wine maturation. Vinification was conducted in 100 L fermenters. All wines were fermented < 1g/L residual sugar and MLF was done after alcoholic fermentation. The phenolic composition was analyzed using HPLC-DAD/FD, LC-QToF-MS and different spectrophotometric assays. The descriptive sensory analysis has been conducted using 19 trained judges.

RESULTS: The sensory analysis showed a higher variance between the wines due to berry maturity than due to maceration time. The sensory perception of wines made out of berries at different stages of ripening could not be influenced towards another stage by extending maceration time. Wine maturation was responsible for the highest variance in phenolic composition. Berry maturity had the lowest impact of the three factors. These observations were made for both grape varieties.

CONCLUSIONS: The analytical methods are well suited to identify and explain the differences of the wines due to maceration time and wine maturation.

The strong influence of berry maturity on sensory perception cannot be explained solely by the phenolic composition of the wines. Further research is needed to identify other parameters that contribute to berry maturity and their interactions with polyphenols to improve the understanding of the term “phenolic maturity”.

This study shows that the oenological tool of extended maceration cannot compensate insufficient berry maturity in regard to sensory perception.

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