Does Wildfire Smoke Damage Wines

In October, 2017, significant portions of California Wine Country were besieged by wildfires that damaged or destroyed many homes, some wineries, and a few vineyards in Napa, Sonoma, Mendocino, Lake, Butte, and Solano Counties.  Most of us stared in disbelief at the TV news stories, and somewhere in the back of our minds was the question, “How will these wildfires and the smoke they produced impact the California wines that I know and enjoy?”  This post covers some of the key issues and points-of-fact involved in this unfortunate, and sometimes tragic situation. 

First of all, only a small part of the wine industry was damaged or destroyed.  Most vineyards were unscathed, or only marginally damaged.  However, there were major losses in several residential areas, especially around the city of Santa Rosa, in Sonoma County.  It was fortunate that the 2017 California grape harvest was essentially complete, and a huge majority of the wine to be produced was already in either tanks or barrels in winery storage facilities. 

The question asked of me on several occasions has been about how the grapes and wines will have been impacted by the fires and smoke.  After some research into this subject, I decided to provide some information on how wildfires and their smoke can impact wines.  One issue was that for periods of time, sometimes several days, winemakers and winery workers were unable to reach their workplaces.  If wines, particularly red wines, were in the fermentation or maceration process, their progress could not be monitored, nor could regularly-scheduled procedures, like punch downs or pumpovers be done.  These missed procedures are not expected to a significant impact on wine flavor or quality.  And that is good. 

A second concern is whether wines or grapes will be infused with smoky aromas or flavors, or essentially be smoke-tainted.  The UC-Davis Extension Service has reported that smoke in or around a winery should have no impact on wines in barrels, tanks, or bottles.  This is good since most of the 2017 vintage was in containers, and all of the 2016 and earlier vintages were also protected inside barrels or bottles.  So, unless a winery or storage facility suffered direct fire or heat damage, no negative impacts on wines should be expected. 

A more interesting question involves whether grapes still hanging in a vineyard would be affected by smoke.  Based on previous experiences in California, most wine-industry folks do not think that the relatively fleeting smoke experience on 2017 will have much impact on grapes.  Most areas were affected by smoke for only short periods of time, most no longer than a week.  However, particles of soot and smoke could be attached to grapes and eventually end up in the fermentation, maceration and aging process.  Thus, only time will tell whether smoky character will be captured in a wine made from grapes that were exposed to significant amounts of smoke.  The expectation for 2017 is that very little smoke-taint will be observed, primarily because most grapes had already been harvested prior to the wildfires. 

One perhaps unexpected result from the wildfire situation is how effective the still-green vineyards were at forming firebreaks.  In well-manicured vineyards, there was little or no undergrowth to burn, and the vines themselves resisted combustion.  Sometimes the advance of flames was stopped at a vineyard, while other times the flames, driven by high winds, had to jump over a vineyard in order to continue their destructive path.  In some instances, when workers could reach their vineyards, irrigation was started to further retard wildfire advance and damage.  Finally, vines that were damaged will be pruned back and new growth is expected next spring.  This means there will be minimal long-term negative impact on vineyards in the wildfire areas. 

Although most of the news regarding California wine that endured the 2017 wildfires is good, there are a number of sad and tragic stories.  Many people who work in California vineyards and wineries lost their homes and most of their possessions.  There were a small number of wineries and wine storage facilities that were destroyed or damaged by flames or intense heat.  Recovery from those losses will require time, money and patience.  Our best wishes go out to those so impacted. 

Because wildfires can also be a threat to agricultural areas here in Texas, it is important to learn from the California experience.  Keeping vineyards well-manicured, maintaining adequate fire-break areas around winery buildings and homes, and developing sound emergency procedures are all important steps to prevent wildfire damage to our beloved Texas Wine Industry. 

A recent article in WineMaker magazine, Feb-Mar 2018 Volume 21 No. 1, entitled Fires in California Wine Country by Alison Crowe, provided the inspiration and a lot of good background information for this Carl’s Corner post.