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Abstract:The current understanding of the influences of climate and viticultural practices on fruit quality at harvest and on sparkling wine quality is reviewed. Factors such as variety, clone, planting density, pruning method, local climate and soils, and current and future climate warming are discussed in the context of achieving a desired harvest quality. A common observation was the relatively less intensive viticultural management applied to grapes destined for sparkling wines compared to table wines throughout the world. Few studies have focused on management of fruit specifically for sparkling wine production. Given that it is accepted that a lower pH, higher titratable acidity, and lower soluble sugars than table wine are considered desirable for sparkling wine production, the literature from viticultural studies for table wines which influence these desired fruit quality parameters has been reported. Specific findings on canopy management, leaf removal, and yield manipulation for the production of table wines indicate potential for application and development to optimize fruit for the production of sparkling wines. Fruit quality targets are remarkably uniform across international growing regions but distinct combinations of variety, clone, and management are currently used to arrive at those targets. Further, studies of viticultural management, particularly those that alter cluster temperature and exposure to incident light, yield manipulation, and fruit quality are likely to best inform production techniques that result in fruit quality ideal for the production of premium sparkling wines. New challenges include the need for increasing mechanization to maintain cost-effective production and climate warming, which affects the production of fruit for premium sparkling production in terms of flavor development and high acidity. Current trends include the diversification of growing regions to cooler regions that enable the production of high acid fruit and increased exploration of alternative varieties and clones that are better suited to a warmer climate.

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The feasibility of an ultraviolet-visible (UV-Vis) spectral phenolic fingerprint (SPF), combined with principal component analysis (PCA), is evaluated as a rapid, simple, and reliable technique for the discrimination of grape juice press fractions destined for the production of sparkling white wines. Juice press fractions of Vitis vinifera L. Chardonnay and Pinot noir grapes comprising free-run (i.e., juice released during the loading of press), cuvée (i.e., first press fraction), and taille (i.e., subsequent press fraction), were analyzed by SPF combined with multivariate data analysis. Two trials were carried out, a laboratory and a commercial scale trial. In both trials, cuvée and taille of Chardonnay and Pinot noir grapes were clearly separated in their corresponding PCA plots based on their SPF. The proposed method enables a rapid and objective discrimination of juice press fractions, which can be obtained using relatively inexpensive UV-Vis spectrophotometric equipment. Insights arising from this research suggest a future possibility of objective, real-time discrimination of juice quality that could liberate the winemaker from tasting juice at the press.