B.C. wine: Researchers assessing wildfires’ impact on smoke taint

Grapes and wine are affected differently depending on the intensity, duration and proximity of a wildfire, and what kind of wood or material is burning

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Researchers in B.C., Washington state and Australia are trying to figure out what levels of wildfire “smokiness” wine drinkers might be willing to accept in their glass so winemakers can decide what grapes to keep or dump.


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“There needs to be a way to effectively test the grapes prior to your going to the expense of picking them, crushing them, fermenting and bottling them,” said Al Hudec, a lawyer with Farris LLP who advises the B.C. wine industry, which is reeling from a summer of out-of-control wildfires in the Okanagan region.

One place at the forefront of the research is Oregon State University, where assistant professor Elizabeth Tomasino said winemakers could benefit from knowing which wildfire-induced chemical changes in their grapes and wine would lead to them being rejected by consumers.

After wildfire smoke blanketed Oregon’s Willamette Valley in 2020 for 10 days and affected more than 500 wineries, Tomasino’s team tested grape and wine samples to record changes in certain chemical compounds. This allowed some winemakers to make business decisions such as halting a harvest.


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Out of this came another project to gather more information. Just exactly what compounds lead to smoky tasting wine? What levels might still be acceptable to most drinkers? Could applying a spray to grapes beforehand help?

The goal is to have a database of information about smoke exposure to grapes, including how the intensity, duration and proximity of a wildfire, and what kind of wood or material is burning, can all change the outcome.

There won’t be firm numbers. “It’s not as cut and dry as people think,” said Tomasino, but winemakers could eventually use research like this to make decisions and assess their options.

It takes time to know what these might be because chemical compounds change as grapes ferment and as wine ages, meaning that any smoky taint absorbed by growing vines isn’t released until later.


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“If you go to all of that expense, and then the smoky taint appears in the final product, you’ve gone through a lot more expense than you would have had to than if you could have identified upfront there was going to be a problem,” said Hudec.

Wildfire smoke passing through the South Okanagan region, taken from Burrowing Owl Winery near Oliver.
Wildfire smoke passing through the South Okanagan region, taken from Burrowing Owl Winery near Oliver. Photo by Instagram: vogon_poetry_society /DEVIN BLANEY via REUTERS

He said most grapes in the Okanagan are sold under either an oral agreement or basic contracts that don’t include well-defined provisions for rejecting shipments for smoke tainting.

“We’re really only having this conversation starting this year, but for the last two or three years it’s been an extremely active discussion in California. There have been a lot of grapes rejected in California.”

“Last year, we tested 4,000 samples from California, Oregon and Washington state as well as wineries here,” said Rob O’Brien, CEO of Kelowna-based Supra Research and Development.


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“When the levels (for chemical markers) are high enough, it can be clear that the grapes are going to be problematic,” said O’Brien. “But at the lower levels, there can be more questions.”

Supra is funding research being done by University of B.C. Okanagan chemistry professor Wesley Zandberg that is trying to fill in some of the missing pieces.

“Some of these chemical compounds are more obnoxious than others. Some of them are really rancid,” said Zandberg. But “others, you can have a thousand times more, and it’s not a problem.”

Zandberg said the B.C. wine industry needs data based on the kinds of trees and grapes that specifically grow here even as research is being done elsewhere since the contributing factors can be very local.


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“In Australia, they have eucalyptus trees. They have brushfires. They have farmers that burn barley and things like that to clear their fields. So the aroma of the smoke is different,” said Zandberg. “In B.C., we have a lot of ponderosa pine.”

It could take years to compile a fuller picture, but there is more interest in the effort than before, said Tomasino.


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Source: vancouversun.com