Influence of berry diameter and colour on some determinants of wine composition ofVitis vinifera L. cv. Riesling

Abstract

Background and Aims To successfully use berry sorting in winemaking, it is crucial to understand the interaction of physical and chemical composition of berries. The aim of this study was to investigate the relationship between berry diameter and colour and aspects of wine composition, such as titratable acidity, aroma compounds and phenolic substances of Vitis vinifera L. cv. Riesling. Methods and Results In a first trial, berries were sorted into three berry diameter classes with equal TSS concentration and vinified by 70 mL scale fermentation. In a second trial, berries from each of two diameter classes with equal TSS concentration were sorted by berry colour to obtain samples of low a* value and high a* value berries for the respective diameter class, and vinified. In the first trial, wines from smaller berries had lower titratable acidity and a lower concentration of malic acid. In the second trial, wine obtained from berries with higher a* values showed a higher concentration of free C13‐norisoprenoids as well as free and glycosylated monoterpenes. Wines from smaller berries in this trial showed a higher concentration of norisoprenoids and a lower pH. Conclusions Berry diameter and colour are highly variable within single vineyards, vines and single bunches. Sorting by berry size or colour will lead to wines with a pronounced difference in aroma compounds, acidity and α‐amino nitrogen. Significance of the Study This study shows the relationship between berry diameter or colour and wine quality aspects such as acidity and aroma. Understanding this relationship will assist winemakers to conduct targeted berry sorting.

The Effect of Elevated CO2 on Berry Development and Bunch Structure of Vitis vinifera L. cvs. Riesling and Cabernet Sauvignon

“…Regarding the proportion of the different berry size groups Riesling showed the highest proportion for berry size groups 5 (12.5-14 mm) and 6 (14-16 mm), which was in accordance with previous literature [19]. In contrast, Cabernet Sauvignon berries were almost entirely in classes 4 (10-12.5 mm), 5 and 6.…”

“…So far, on white cultivars, only greenhouse experiments were conducted, showing that there was no eCO 2 effect on malic or tartaric acid at berry maturity [12,13]. Interestingly, a previous study on Riesling berry size [19] demonstrated that an increase in berry size was associated with increased malic acid concentration, which could account for a direct eCO 2 effect on berry size, and this in turn resulted in an enhancement of malic acid under eCO 2 . A similar achievement was made for Cabernet Sauvignon, resulting in higher malic acid and lower total acid concentration with increasing berry size classes [20].…”

“…Nevertheless, all studies conducted on field-grown grapevines under eCO 2 conditions embraced that there is no positive or negative repercussion of eCO 2 on grape or wine quality [2,3,7]. On the other hand, eCO 2 was shown to affect grapevine vigor and growth, especially bunch and berry weight or berry number [3,6,9], and it could, therefore, lead to quality changes by altered berry sizes [14][15][16][17][18][19][20][21].…”

“…Sangiovese. However, berry size was discussed to be related to berry and wine quality [14][15][16][17][18][19][20][21]. Hence, the quality of grapes grown under eCO 2 might be affected.In other perennial fruit crops like pears and sour oranges, enhanced fruit weight, volume, and diameter were detected under eCO 2 [22][23][24].…”

“…Sangiovese. However, berry size was discussed to be related to berry and wine quality [14][15][16][17][18][19][20][21]. Hence, the quality of grapes grown under eCO 2 might be affected.…”