Interview. Incendies en Gironde : le vin rouge de Bordeaux plus à risque de développer un goût de fumée
By Amandine Bourgoin
Published on
updated on 30 Aug 22 at 13:29
After the fires in Gironde, winegrowers are wondering about the risk of the presence of a taste of smoke in bottles of Bordeaux wine. Philippe Dulong, president of the Union of Oenologists of France in the Bordeaux South-West region, explains this phenomenon that winegrowers in Provence faced after the fires in 2021.
News: After the fires in Gironde this summer, is there a real risk of rediscovering a taste of smoke in Bordeaux wines?
Philippe Dulong: It is not yet known whether this risk exists or not, we must wait for the results of the analyzes. Given the scale of the fire, it is normal for the profession to ask the question. I would be surprised if entire vineyards were affected, perhaps parcels here and there because we know that the taste of smoke is found in vineyards that are close to fires. In Gironde, it would be possible in the Graves area, the Sauternes area, but they were still a few kilometers from the fires.
How does this smoky taste end up in the wine?
DB: You should know that this mainly concerns red wine. The combustion of wood secretes well-known substances, which are volatile phenols. These are the same ones found when grilling meat on vine shoots. The wine sent the smoke, the acrid, the cold ashtray but remains consumable. There’s a lot more on the steak than the bottle of wine, but sometimes it’s not nice.
Volatile phenols have imposed themselves on the surface of the grape at the level of the bloom which captures a large number of molecules from the environment and penetrates the plant. The molecules bind with the sugars and this new molecule composed of volatile phenols and sugar is odorless so tastefully, if the winegrower bites into his berry, he will not be able to perceive the taste of smoke. This is only revealed slowly during fermentation with the yeasts which produce the odorous molecule. It is only at the end of fermentation that we can have the appearance of these tastes.
It is necessary to go through the analysis to see if this bond between the volatile phenols of the fumes and the sugar exists and then to cut it.
How do I get rid of that smoky taste?
DB: With extremely basic treatments used in many other cases of olfactory defects. It is necessary to use b-glucosidase enzymes which make it possible to release the fragrant substances and then they can be captured with bentonite clays, which have been used since the dawn of time to remove the proteins from wines which stick to the clay.
Why are red wines more at risk of developing this unwanted taste than other wines?
DB: For red wine, the skins are macerated with the bloom in the grape juice for fermentation, which is not the case for whites or rosés which are pressed. The risk is therefore less, but not impossible. Last year in Provence after the fires, winegrowers found smoky tastes on rosés.
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