2018 has been a rough year for the West Coast, with major wildfires blazing in California, Washington, Oregon and other states. At times, it’s seemed like the whole area was continually ablaze; last month, a disturbing satellite image showed a shroud of smoke hanging over 110 large wildfires. Such fires have had devastating effects on residents, leading to mandatory evacuations, staggering property losses, and, sadly, a number of fatalities.
Of course, natural disasters affect local economies as well, and one of the West Coast’s most important ones—the wine industry—is suffering the effects of all those fires, too. Last year, more than 11 California wineries were irreparably damaged or destroyed; this year, while outright damage has been more limited, a significant threat still hangs in the air: smoke taint.
When wine grapes are exposed to smoke for a prolonged period of time, the fruits can absorb smoky compounds through their skins, ultimately leading to off flavors in finished wines that, instead of evoking earthy tones or fruity finishes, can taste more like a cigarette butt. It’s an issue many West Coast wineries are rightly concerned about; given that vineyards pour time, effort, and expense into maintaining perfect growing conditions for their grapes, they certainly don’t want wildfires, or any phenomena over which they have no control, to spoil part or all of their bottlings.
But as chemist and wine expert Tom Collins explained, it can be difficult for wineries to tell if their grapes have been affected by smoke or not. Should they go through the expense of aging and bottling affected fruit? Or will they just have to dump the product later?
“What we’re trying to do is to let growers and wineries make better decisions about what to do with fruit that’s been exposed,” he told MUNCHIES.
Collins, an assistant professor at Washington State University’s Wine Center, is the lead researcher behind the Center’s smoke taint study, which aims to identify the myriad problems posed by environmental fires, and how to solve them. Since 2015, he has been smoking out sections of his research vineyards in an effort to understand what happens to the fruit—and, ultimately, the wine—when subjected to such conditions.
“The basic question is, how much smoke exposure does it take to create a problem in the grapes, and in the resultant wines?” he said.
To run the experiments, Collins covers sections of the vineyards with a canvas tent and pipes in smoke from a smoker set outside the tent. The process continues for 48 hours, a period of time similar to real-life exposures from actual wildfires. There’s enough fruit in the vineyards to make a small amount of wine, which Collins analyzes chemically and evaluates its taste. He compares these measures to wines made from unaffected grapes from a control section of the vineyard.
“We try to tie changes in the composition of the fruit to an ability to perceive the problem,” he said.
Smoke taint-affected wines can vary in flavor, but the result is not a desirable one, Collins said.
“A number of descriptors have been used to describe the taste,” he said. “Ashy, smoky, cigarette smoke, cigar butt.” The worst of the affected wines cannot be sold, Collins added.
Last year’s wildfires were so bad that wineries in California, Washington and other states were forced to dump wine made from the smoky grapes, or blend the wines in an attempt to make them more palatable. That kind of outcome wastes vintners’ time and money, and it’s one they’re looking to avoid as wildfires become a matter of course during the hot, dry summer months.
“In the aftermath of some of the fires from last year, there was a lot of interest in my work,” he said.
Because 2018’s wildfires haven’t been nearly as bad as last year’s, it’s unclear whether their smoke will affect this year’s vintages. But that’s exactly what Collins’ work aims to establish: measurable outcomes that can help winemakers decide how to proceed with fruit that they suspect, but don’t know for sure, has been affected.
“One of the big goals of the project is to develop the ability to predict when a smoke exposure is a problem for the vineyard or the winery,” he said. “If the answer is, ‘Yes there was enough smoke exposure that this fruit has a problem,’ then what are the options for cleaning it up and making it usable?”
Some ideas Collins is looking into include reverse osmosis systems and enzymatic treatments that could help clean up the smoky flavor of an affected wine. But, Collins cautioned, “we want to make sure we’re doing minimal damage to other things that are present in the wine.”
Collins’ research project is currently in its third year, and he’s drafting a proposal to continue it for another three years. Given that global warming is making dry areas even drier, effectively turning western forests into kindling during the hot summer months, it’s likely that vineyards will increasingly be faced with the problem of smoke taint and how to navigate around it.
“I expect it will continue to be an issue,” Collins said.