Crops altered by droughts, floods and other extreme weather phenomena: climate change has entered the world of viticulture. How to reduce the impact of these hazards on the production and quality of the grape? A challenge that Sicarex – the technical body at the service of Beaujolais wines – has decided to tackle head-on: its “Château de l’Éclair” estate serves as a testing ground for new viticultural techniques.
Anti-hail nets, modification of the height of the stems, establishment of new grape varieties: in the Beaujolais vineyard, on a “guinea pig” plot, various responses to climate change are tested to help farmers adapt to the ups and downs of the weather .
The blazing sun which overwhelms the vineyard at the end of the September afternoon illustrates the theme of the “open plot” operation conducted that day by Sicarex, the technical body serving Beaujolais wines. : “discovery of the different levers for adaptation to climate change”.
His estate, Château de l’Éclair, acts as a full-scale experimentation field with a view to “producing objective technical references to guide the choices” of winegrowers, according to its director, Bertrand Chatelet.
The observation, summarized by this official, is established: climate change, “these are very contrasted, extreme periods. When it rains, it’s a long time and a lot, violent storms, strong freezes, or higher temperatures on longer phases, which influences the composition of the grapes, in terms of sugar and acidity “.
Extend the cycle of the vine
How to cope? Coming from several of the 12 Beaujolais appellations, a strip of about fifty kilometers stretching north of Lyon, winegrowers and students roam this sometimes very steep terrain in search of tracks.
Here, for example, are rows of vines set in anti-hail nets. If they protect the grains from precipitation, these nets also produce a “shading effect”, explains Taran Limousin, of the Institut de la vigne et du vin (IFV), a partner of Sicarex.
“The radiation drops by 30% and the berries suffer less from water stress: they sweat less, need less water and therefore pump less into the soil. In the event of drought, this is an advantage.” However, it costs around 15,000 euros per hectare – excluding aid – to install such a device.
A few rows further, we test the height of the leaf hedge. In general, the trunk measures 60 cm, there it passes to 90 cm: by reducing the quantity of leaves and therefore photosynthesis, “the objective is to lengthen the cycle of the vine”, details Jean-Yves Cahurel, of the IFV.
Later maturation would thus shift the harvest by as much, to a period “when it would be less hot” and the necessary balance between sugar and acidity would be better respected. The first tests are considered “encouraging”.
Another room for maneuver: intervention on the grape variety itself. Extracts from the Sicarex conservatory, Gamay vines – the main grape variety in Beaujolais – which were no longer used because they have a late maturity are, for example, selected and replanted.
Likewise, during tests on grape varieties resistant to downy mildew and powdery mildew, and therefore requiring fewer phytosanitary products, those which also show late maturity will be selected. “It’s important to find the grape variety that meets both environmental and climatic issues,” comments Sylvain Paturaux, 41, who took over an estate in the Fleurie appellation in 2020. And to remember that “the vine is a long time, because we plant for about thirty years”.
Grape varieties from the South are coming further north
But the most original aspect, in the land of Gamay-Roi and Chardonnay, remains the experience of introducing grape varieties typical of the south of the Rhone Valley that take more heat, such as Syrah or Viognier.
In Quincié-en-Beaujolais, at an altitude of 450 meters, the Château de Varennes has planted 1.8 hectares, out of 20, for a first harvest these days.
“Within ten years, with the warming, this type of grape variety, ideal for the south will also become so for the north,” says manager Pierre-Olivier Sauvaire, remembering the scorching harvest – 36 ° C – in 2020.
For the owner of the estate, Nicolas Gauvin, the climate dimension was not, however, a priority in the approach. It was “first and foremost to expand our offer, with grape varieties enabling customers to find Côtes-du-Rhône lovers”.
Future bottles, moreover, cannot be marketed under the Beaujolais-Village appellation. They will be IGP Comtés-Rhodaniens.