From grapes to sparking wines: Aromas evaluation in a vine-spacing

Aim: Wine aromatic profile is a combination of viticulture and oenological practices and it is related to character, quality, and consumer acceptance. Based on the competition between soil capacity and canopy development, and on the potential to produce sparkling wines at Caldas, in the south region of Minas Gerais (Brazil) (21°55´S and 46°23´W, altitude 1.100m), the aim of this work was the evaluation of the development of aromas (secondary metabolites) from grapes to sparkling wines in a vine-spacing experiment and whether the distance between the vines can influence the aromatic profile of the sparkling wines (final product). 

Methods and Results: The study was conducted with grapes from a 7-year-old vine-spacing experimental vineyard located at Caldas city and their respective must, base wine, and sparkling wine from vintage 2016 of the cultivar Chardonnay (Vitis vinifera L.) grafted onto 1103 Paulsen rootstock, in a clayey soil, and trained on a vertical shoot positioned trellis. Grapes were harvested in the maturity stage for sparkling wines, which were obtained by the traditional method. The volatile compounds in the specimens described were analysed by HS-SPME/GC-MS. Considering the five vine-spacing systems studied (0.5 m, 0.75 m, 1 m, 1.5 m, and 2 m), around 60-80 volatile compounds (secondary metabolites) were identified in the free form for all the specimens studied and PCA analysis showed discrimination among them. Thus, some compounds were slightly higher in must and wines than in berries (e.g., terpenoids, carotenoids). While in the grapes and must the high number of compounds was related to aldehydes and alcohols, in the base and sparkling wines it was related to esters, benzenoids and fatty acids compounds. These compounds resemble pleasant, powerful, floral, fruity odours of apricot and pineapple-banana note, and have an influence on foam.

Conclusions: 

All the processes (grapes metabolism, first fermentation and sur-lie) influenced the development of the aromas. Although the aromatic profile of the five vine-spacing systems sparkling wines was slightly different, a sensorial analysis would be an additional tool to this work to assess if these variations would be noticed by final consumers. 

Significance and Impact of the Study: This study impacts on the knowledge of the products obtained in this terroir, in which conditions one can have a product that pleases the final consumer more and also has a good production. In other words, the consideration for the balance among grape-growing and winemaking practices, productivity/economy, and quality of the final product.