Notes of ashtray
How forest fires can spoil wine by creating ‘smoke taint’ and ashiness
Even when vineyards escape being scorched by wildfires, the remaining smoke can have lasting ramifications. Wine made in regions that are often affected by forest fires — such as Australia, California or Southern Italy — can have undesirable smoky aromas.
But until recently, no one knew exactly why.
While smoky or toasted aromas are welcome in some wines; “smoke taint” is decidedly unpleasant, adding notes of “ashtray.” In a new study, researchers at the Technical University of Munich explain why smoke taint occurs in wine. Their findings were published in the Journal of Agricultural and Food Chemistry.
When grape vines are exposed to fire while they’re growing, the plants absorb the aromatic molecules, which attach to sugar via a protein called glycosyltransferase. “The aroma can be retained or stabilized with this sugary compound. The aromatic substance can then once again be detached from the sugar and released. This process is called glycosylation,” the research team said in a statement on ScienceDaily.
Unfortunately for winegrowers, smoke taint isn’t detectable until fermentation takes place. “It only becomes apparent in the finished wine that the vineyard was exposed to a fire and the final product is of poor quality,” study author Katja Härtl said in the statement.
“We now know how such a taste can develop,” team lead Prof. Wilfried Schwab added. “In the next step, we can try to cultivate either grape vines with less glycosyltransferase. Or we’ll add a second sugar to prevent the release of the bad aromas.”
Winemakers in B.C. weathered the province’s most severe wildfire season ever this year. (According to Global News, 894,491 hectares have burned since April 1.)
The Vancouver Sun reported that Okanagan wineries “are confident” the smoke hasn’t contaminated their grapes, but are unable to say definitively until the wine is made.