My DNO (Diplôme National d’Œnologue) class in Toulouse recently visited the IFV V’innopôle station in southwestern France. This is one of eighteen Institut Français de la Vigne et du Vin centers located throughout the country. Our class had visited an INRA (Institut National de la Recherche Agronomique) research center last year to see wine filtering technology that is being developed there.
Whereas INRA does fundamental research, the IFV tests new technology and vineyard management techniques. The object is to transfer this technology to students (such as those in my class) and French winemakers. There are 13 engineers and technicians working at the V’innopôle, specializing in different vineyard and winemaking areas that include plant biology, soil and water conservation, agricultural equipment and oenology.
The center, which is located in a wooded area near the Gaillac wine region an hour and a half northeast of Toulouse, is one of the most important grapevine conservatories in France. More than 340 different grape varieties are found in the research vineyards that surround the V’inopôle. Besides preserving many of the native grape varieties found in southwestern France, these vineyards are also used to test new soil management, vine cultivation and insect control techniques.
The center’s director, Eric Serrano, and one of the center’s technical engineers, Virginie Vigues, told us about some of the 35 experimental programs underway here. Vigues is coordinating a campaign that uses computer modeling to predict and analyze the risk of fungal and other plant diseases to the region’s vineyards. A network of 40 meteorological stations has been placed throughout the region. Data from radar images provided by Météo France is being integrated with this meteorological data to inform area winemakers on the best time to treat their vines. She said that the average annual number of phytosanitary treatments has been reduced by almost 50% since the system was implemented in 2007, decreasing significantly the amount of chemicals used in the vineyards.
Another area of research involves evaluating the aromatic qualities of different grape varieties. Chemical analysis of aroma precursors and polyphenols in the grapes is involved, but they are also studying how vineyard practices and winemaking procedures affect grape aromas. We had a chance to taste a dozen or so wines that have been vinified in the center’s wine cellar as part of this research. The peppery aromas typical of the Gaillac region’s Duras grape variety, the violet aromas of Negrette grapes from Fronton, and the sulfur-containing compounds called thiols that are largely responsible for the grapefruit, asparagus, and peach aromas of the Colombard grapes native to southwestern France’s Gers region are just a few of the varietal aromas being studied.
Thermovinification, or hot maceration, where the grapes are rapidly heated to above 80°C and then cooled to around 30°C in a vacuum chamber, was used to extract the maximum varietal aroma in the wines that we sampled. The process explodes the grape cells to remove the polyphenol flavor compounds. It also increases the extraction of anthocyanins, the color compounds found in red grape skins, deepening the wine’s color tints. This industrial process was developed by INRA to permit wine cooperatives in the Languedoc region to process huge quantities quickly and efficiently.
Although I wouldn’t consider thermovinification as a way to improve wine (other than wine made from substandard grapes, e.g., over-ripe or even grapes attacked by bacteria), it does provide a way to study the different aromas that are characteristic to different grape varieties.