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Background and Aims According to one of the classical postulates of viticulture, cultivars with smaller berries produce the best red wines. During grape development, some differences at berry level lead to a wide range of fruit heterogeneity at harvest. One source of heterogeneity at harvest is berry size. The aim of this work is to determine if berry size affects the colour and chemical composition of wine. Methods and Results Cabernet Sauvignon grapes were harvested at optimal ripeness, and screened by two sieves, to select three groups of grapes of large, medium and small size. Wines were made from each size class in triplicate, with the control being wine made from unselected grapes. The colour properties and composition of the phenolic substances of the wines were determined. Conclusions Wine colour showed the clearest trend in this experiment: the smaller the berries, the deeper the wine colour, as measured by the CIELab coordinates as well as by (wine) colour intensity. Moreover, stilbene concentration increased when berry size decreased, while pH did the opposite. Finally, wines made from small berries had a titratable acidity, total phenolic index and monomeric flavan-3-ol concentration higher than that of wines made from the large- and medium-sized berry sizes. Significance of the Study These data suggest that berry size classification in wineries would be an interesting tool for management of wine composition. [ABSTRACT FROM AUTHOR]

Background and Aims: δ13C values from Vitis vinifera leaves, whole grape, seed, pulp, skin and/or grape must sugars have been investigated as an integrated marker of vine water status or intrinsic water-use efficiency during berry growth and across region of origin, vintage and variety. The use of 18O/16O isotopic ratio as a marker of water addition, vintage and geographical origin has also been studied. This paper examines the effect of irrigation and grapevine variety on δ18O and δ13C of grape must from eight varieties, all cultivated in the same vineyard to reduce the effects from other variables. Methods and Results: Stable isotope compositions of grape must water and sugar were determined by isotope ratio mass spectrometry. The result of the study showed statistically significant effects of irrigation and vine variety on both δ18O and δ13C. The effect of vintage on δ18O was only significant for non-irrigated vines. Conclusion: This research highlights the effect of variety and irrigation on δ13C and δ18O of grape. Significance of the Study: This is the first report to demonstrate that the varietal effect on δ13C and δ18O of grape is not due only to differences in the vegetative cycle of each variety. It further suggests that water exhibits a lower isotopic discrimination in the indigenous Spanish varieties studied than in non-indigenous varieties. [ABSTRACT FROM AUTHOR]