Wine made from grapes exposed to wildfire smoke does actually taste smoky, according to new research out of the University of British Columbia.
Researchers found chemicals in the smoke that can give wine “smoke taint,” as volatile phenols are absorbed into the grapes quickly and stay long after the smoke clears.
The grapes taste and smell normal, found researchers, and it was only when they were fermented into wine that the smoke could be detected.
“The biology of how wine grapes respond to smoke exposure is poorly understood,” said Wesley Zandberg, assistant professor of chemistry, in a release.
“Winemakers know that grapes grown in smoky conditions can lead to smoky-flavoured wine although the grapes themselves taste normal, and how or why this happens has largely remained a mystery.”
Last year’s wildfire season was the worst in BC’s history, after wildfires ripped through more than 1.2 million hectares of land, with smoke memorably spreading as far as Vancouver.
To find out how that affected the region’s wine, UBC researchers worked with their industrial partner Supra Research and Development to replicate BC wildfire conditions.
Zandberg, together with PhD student Matthew Noestheden and research associate Eric Dennis, exposed Cabernet Franc grapes to smoke from Ponderosa pine and local leaf litter.
Cabernet Franc grapes are black grapes, often used for blending with red wines like Cabernet Sauvignon and Merlot. In Canada, they are also made into ice wine.
Researchers tested the Cabernet Franc grapes for volatile phenols several times after smoke exposure and in wine made from the same grapes.
“We found that once the grapes were exposed to smoke, the volatile phenols were rapidly metabolized by the grape and stored, in part, in a sugary form that we can’t taste or smell,” says Noestheden.
“Once there, the concentrations remained unchanged in the grape throughout its development. Only when the grapes were fermented into wine could the smoky-flavoured volatile phenols be detected.”
So what can you do about this? Well, one idea is overhead irrigation – but researchers found that didn’t actually work.
“We washed the berries to simulate the use of an overhead irrigation system and we were surprised to learn that it didn’t seem to affect the concentration of volatile phenols at all,” said Zandberg.
We’re not sure whether that smoky wine will be making it the shelves, but if your glass of Cab Sav does taste a little smoky, now you know – it’s not your imagination.