Qualité des vins et Terroirs. Incidence du milieu naturel sur la composition aromatique des vins

Berry shriveling (BS) in vineyards are caused by numerous factors such as sunburn, dehydration, stem necrosis. Climate change results in an increase in day and night temperatures, rainfall throughout the year, changes in the timing and quantities, long dry summers and a combination of climatic variability such as floods, droughts and heatwaves). Grape development and its composition at harvest is influenced by the latter as grape metabolites are sensitive to the environmental conditions. The grape berry experiences water loss and an increase in flavour development as a result of the BS. An increased sugar content in grapes will result in higher alcohol wines and concentration of grape aromas which may be detrimental to the final wine quality.

The wine sector is being directly affected by climate change. Temperatures above 30ºC can cause a lag between the ripening of the berry pulp (a rapid increase in sugar content) and the skin

The Agenda 2030 of the EU sets out the main guidelines for transitioning towards a resilient, green and safe economy. To this regard, the wine sector is experiencing an ecological transition in different ways such as increasing the production of ecological crops, or promoting the production of wines under more environmental-friendly and healthier (i.e., lower levels of SO2) products. These alternatives to conventional production are a smaller proportion of wines, in constant growth and demand, and follow alternative and minority practices, which range from sustainable to deeply philosophical thoughts. Among these methods there are organic, biodynamic and, more recently, natural wines.

Chemical and sensory changes occurring in red wine during ageing in oak barrique are due to the slow and gradual entrance of oxygen along with a release of ellagic tannin from the wood. Though oxygen can enter the cask through the bunghole, it is not clear the role of permeation through the wood staves as well as the amount of oxygen entering by permeation. The distribution of the released ellagic tannins in the wine ageing is also unknown. The oxygen passing through the bunghole may have a different wine ageing effect compared to the oxygen permeating through the wooden staves owing to the uneven ellagic tannin concentration throughout the wine.

On the market there are several wine grapes which are tolerant to the main fungal diseases. These varieties, commonly defined “resistant”, were developed in the grapevine breeding programs carried out mainly in Germany, France, Hungary and Italy. Some of these cultivars have been included in the national catalogues of wine grape varieties and have sometimes been allowed for specific kinds of wine. The VEVIR project, aimed at the enological evaluation of resistant vines, involves 33 cultivars achieved at the State Institute for Viticulture Freiburg in Germany, the Research Institute of Viticulture and Enology Pecs in Hungary and the Fondazione Edmund Mach S. Michele all’Adige (FEM) in Italy.