Smoke flavour hides in wine grapes, say researchers

VANCOUVER Smoky overtones can ruin a nice bottle of wine, but researchers in British Columbia are finding that preventing grapes from capturing the flavour of wildfires can be difficult.

Wine grapes absorb smoke compounds, surrounding them with sugar, explained Wesley Zandberg, an assistant chemistry professor at the University of British Columbia in Okanagan.

The chemicals, known as volatile phenols, can’t be detected when you eat or smell the fruit, but during the fermentation process, yeast cuts the sugars off, releasing flavours and smells that aren’t necessarily pleasing to the palate, he explained.

“It wouldn’t be a problem if smoky flavoured compounds got stored in grapes and they just kind of hung out there and I could never taste them,” Zandberg said.

“I can eat the grapes, I can test the grapes before fermentation, they taste great, they smell great, and then as soon as I put the yeast on them, I find that I’ve got terrible tasting wine.”

Zandberg and his team did field testing in British Columbia’s wine region, an area in the Okanagan that’s also susceptible to wildfires.

The researchers built a structure over some grapes and pumped in smoke, simulating the burning of foliage that grows in the region. They then compared the composition of the smoky grapes to fruit that grew on a nearby vine, free of smoke.

Zandberg said his team found the grapes absorb the smoke quickly, within about an hour, and can’t be stopped by washing the grapes with water.

That makes it hard to protect the fruit from wildfire smoke, he said.