Techniques for sunburn reduction in bunches in Vitis vinifera L. cv. Graciano

The selection of a suitable grape variety (Vitis vinifera L.) for specific viticulture and oenology objectives is a considerable challenge in the context of climate change.

The study of the interaction between vineyards and the environment to establish the grapevines in the appropriate places has been applied in wine science for 5000 years. Advances in the field of the zoning have not been uniform in time, and have occupied a preferential place in the contributions of Roman writers of the 1st Century AC, the contemplations of Tokay (1700) and Porto (1756) and works of the second half of the 20th century. Zoning practices today integrate multidisciplinary methodologies (viticulture, enology, soils, climatology, cartography, statistics, computer science) and require further development for future application.

Estimation of the resistance of a wine against oxidation is of great importance for the wine. To that purpose, most of the commonly used chemical assays that are dedicated to estimate the antioxidant (or antiradical) capacity of a wine consist in measuring the capacity of the wine to reduce an oxidative compound or a stable radical.

Using viticultural and enological techniques to increase aromatics in white wine is a prized yet challenging technique for commercial wine producers. Equally difficult are challenges encountered in hastening phenolic maturity and thereby increasing color intensity in red wines. The ability to alter organoleptic and visual properties of wines plays a decisive role in vintages in which grapes are not able to reach full maturity, which is seen increasingly more often as a result of climate change. A new, yeast-based product on the viticultural market may give the opportunity to increase sensory properties of finished wines. Manufacturer packaging claims these yeast derivatives intensify wine aromas of white grape varieties, as well as improve phenolic ripeness of red varieties, but the effects of this application have been little researched until now. The current study applied the yeast derivative, according to the manufacture’s instructions, to the leaves of both neutral and aromatic white wine varieties, as well as on structured red wine varieties. Chemical parameters and volatile aromatics were analyzed in grape musts and finished wines, and all wines were subjected to sensory analysis by a tasting panel. Collective results of all analyses showed that the application of the yeast derivative in the vineyard showed no effect across all varieties examined, and did not intensify white wine aromatics, nor improve phenolic ripeness and color intensity in red wine.

A two years trial was carried out in Chianti (Central Italy) to assess at the detailed scale the viticultural and oenological suitability for Sangiovese of different pedoclimatic conditions, by means of the ΔC13 measured in the must sugars