Will fire be the death of California’s wine industry?

The “beating heart of the American wine industry” has had to reckon with this question since 2017 when numerous wildfires spread across northern California’s famed wine country. The Tubbs, Atlas, and Nuns fires burned hundreds of thousands of acres, caused numerous deaths, and destroyed multiple wineries and vineyards in Napa and Sonoma counties.

The total acreage burned and widespread property damage caused the 2017 wildfire season to be the most destructive in California’s history. That record-breaking year was quickly surpassed by the 2018 and 2020 fire seasons. The 2020 season, in particular, also broke burn records in the other top American wine-producing states of Oregon and Washington, and even Canada in 2021. Wildfires in the years following impacted international wine markets as well, including Italy, France, and Australia.

University California Division of Agriculture and Natural Resources

Intense flames aren’t the only threat wildfires bring to vineyards; it’s also the smoke they produce. A condition called “smoke taint” causes wine grapes exposed to smoke to acquire “unmarketable smoky, burnt, ashy, or medicinal sensory characteristics,” according to the Australian Wine Research Institute (AWRI).

The international wine industry has made it clear that it views wildfires and smoke as existential threats, along with increasing water shortages and climate change as a whole. The industry has poured billions of dollars into research on ways to stave off the industry’s wildfire-caused death rattle. Examples of recent smoke-related wine research in the U.S. include a protective spray coating for grapes, detecting the compounds responsible for the undesirable taste, and using smoke sensors in vineyards for risk assessment.

Oregon State University smoke research
Oregon State University smoke research

Agriculture-based technological developments, however, can only do so much to keep a fire-sensitive crop alive after it’s planted on fire-dependent lands. Grapes, while not technically invasive, have invaded portions of the Western United States’ lands and have largely usurped once highly forested regions where fire played an important ecological role. As prescribed fire establishes a larger role in modern Western land management practices, how long can an industry based on fruit that needs a smokeless environment survive and thrive?

The birth of California’s wine industry is well-recorded: Spanish missionaries planted the state’s first sustained vineyards in southern California during the late 1700s using grapes native to Europe — to make sacramental wine. Wine production then exploded in the northern and central parts of the state during the Gold Rush, paving the way for California’s current top grape-producing counties of Fresno, San Joaquin, and Kern.

What’s not well-recorded is how agricultural land conversions cleared millions of acres of conifer and oak forests throughout the state to make way for vineyards and other crop fields. In Napa and Sonoma counties specifically, areas now known as the pinnacle of “wine country,” modern vineyards sit on land that once supported massive oak forests culturally maintained by the area’s various Indigenous tribes.

“While almost all of the valley oaks are gone from Napa — the savannas were largely cleared to make way for intensive agriculture in the late 19th century — a few pockets remain,” a New York Times article on the Napa Valley Historical Ecology Atlas said. “The oldest trees, dating back more than 300 years, were alive when the Caymus, Napa, Canijolmano and Mayacma tribes managed the valley to produce abundant acorns, deer, salmon, and other staples.”

The clearing of these woodlands was coupled with a government-mandated suppression of cultural burning, a kind of prescribed burning Native Americans used to promote culturally significant foods and resources within a landscape. After a century of fire suppression, the USFS has begun to understand how significant cultural fire is to promoting biodiversity and creating healthy landscapes.

“Colonization and subsequent governmental fire policy mandates have disrupted the cultural use of fire, which in turn has disrupted ecological functions where those fires are absent,” USFS research said. “As society grapples with the devastating impacts of wildfires and the loss of biological diversity, many Indigenous people see traditional fire use as a key to mitigation of devastating losses while retaining traditional livelihoods associated with burning.”

In hopes of preventing future megafires, California increases prescribed burns throughout the state, including wine country. Even though research shows smoke from prescribed burns tends to be less harmful and toxic compared with smoke from wildfires, the grapes themselves don’t seem to care.

“Studies have shown that grapes need to be exposed to only a single smoke event, irrespective of the source, to become ‘tainted,’” AWRI said. “Bushfires, forest fires, planned burns, grassfires, and agricultural burns can all cause smoke taint if smoke from those fires is present in a vineyard at a high enough level for a period of time. Current research suggests fresh smoke presents the greatest risk for smoke taint, but smoke that has drifted hundreds of kilometers has also resulted in smoke taint.”

Efforts have been made for fire planners and wine producers to work together to minimize smoke’s negative effects on wine grapes, but thus far have mostly been in vain. AWRI and other wine industry researchers recommend the best time to conduct prescribed burns to limit smoke taint  is during the height of wildfire season between May and October; before grapevine flowering and after grape harvest. The “usual” best times to set prescribed burns, mid-spring or in the fall, are the most at-risk times for smoke taint in grapes.

The contradiction is clear: Grapes, at least those that winemakers don’t want smoke-tainted, can’t exist in an area with regularly prescribed burns, e.g. California.

Grapes themselves are partly to blame for this. A concept called “terroir” has been used for centuries to describe the deep ecology behind why grapes grown in different places and in different ways acquire different qualities. Everything including temperature, soil, geology, elevation, water quality, wind direction, farming practices, and the winemaking process influences grapes and, by extension, the wine made from them. Even if researchers could 100 percent prevent smoke-taint issues in wine grapes, the grapes themselves would still be affected by the inevitable changes the fire-dependent landscape will experience in years to come.

The irony is that California does have native grapes, which thrived in the state’s pre-colonized and fire-dependent forests. In fact, the global wine industry wouldn’t exist today without California Wild Grapevines, as the species was used to save the European wine industry between 1870 and 1900 when most wine grapes were killed by leaf- and root-attacking aphids. Winemakers, in a last-resort desperate bid, used Califonia Wild Grapevine roots and grafted them onto European grape varieties. The result was a plant with the root resilience of a wild grape and the desirable taste of a European grape.

California wild grapes themselves, however, were originally discredited by European colonists for being too “foxy” and not containing enough sugar. But in a state destined to have more smoke, the more fire-resilient California Wild Grape, whose burnt vines can resprout, may soon be the California wine industry’s only option. One farmer in Sonoma County agrees and is experimenting with more than 30 different native grape hybrids in response to climate change.

The global wine industry is one of stubborn tradition. The industry’s desire to find easy “solutions” to existential problems without systemic change paints a worrying picture of the role California’s vineyards play in the state’s fight against future wildfires. Winemakers can only hide behind the industry’s $70 billion price tag for so long.

There comes a point at which economic benefit is outweighed by potential ecological destruction, and the industry will soon have to decide whether it will play a role in California’s solutions to megafires or actively hamper efforts to help make the state’s landscape healthy. Winemakers in California may soon have to answer the question of “when should this industry die?”

Grapes exposed to wildfire smoke may produce smoke-flavored wine

Wine grapes
Wine grapes. Photo by Fir0002.

From CFJC Today:

A new study out of the University of British Columbia Okanagan has looked at what happens to wine grapes when they are exposed to wildfire smoke.

Researchers found chemicals in the smoke can give wine an off-putting smoky flavour and aroma known as smoke taint — and those volatile phenols are absorbed quickly and remain in the grape long after the smoke has cleared.

The authors say while wine from those grapes can be smoke-flavoured, the grapes themselves taste normal, likely a result of the volatile phenols changing during the fermentation process.