2008 Cal Winegrape Crop Tainted With Wildfire Smoke

2008 Cal Winegrape Crop Tainted With Wildfire Smoke

4 November 2008

published by westinstenv.org


USA — A number of sources are reporting that the smoke from this summer’s wildfires in California may have tainted the 2008 winegrape crop. Megafires from Santa Barbara to the Oregon border poured smoke into the prime Cal winegrape growing regions for three solid months, with probable deleterious effect to this year’s wine vintage.

The Santa Rosa Press Democrat reported in September [here] that

Three months after smoke from wildfires carpeted California’s vineyards, some winemakers in the thick of harvest are reporting grapes giving off unusual odors that may be signs of smoke taint.

While it’s too early to generalize about the scope of the potential problem, some troubling reports are filtering in from Mendocino County, which earlier this summer endured some of the fiercest wildfires and worst air quality in memory.

“Winemakers are saying that they think stuff is smelling funny to them, and they want to know what’s going on,” said Glenn McGourty, viticulture adviser for the University of California Cooperative Extension in Mendocino.

Mendocino County and adjacent Napa and Sonoma Counties were inundated by smoke from the Walker, Mendocino Lightning Complex, and Soda Complex fires, to name a few. Monterey and Santa Barbara Counties endured smoke for months from the Indians, Basin, Gap, and Chalk fires. Northern California counties were choked by smoke from over a thousand square miles of fires that burned for over three months. The San Joaquin Valley suffered smoke-related air pollution from dozens of fires including the Clover, Hidden, Tehepite, and Telegraph Fires.

Over 2,000 fires burned well over a million acres in California this summer. Most of those were ignited by a dry lightning storm that swept the state June 21st. Although most of the fires were extinguished with a week or two, many were allowed to burn all summer long. USFS fire management policies of whoofoo (Wildland Fire Use) and hammer (Appropriate Management Response) led to extended burns that were still smoking in October.

Whoofoos are supposed to “benefit” resources, although the specific resources and the specific benefits are never mentioned in whoofoo reports. In any case, California’s wine industry did not benefit from summer-long smoke.

The Cal wine industry is a $100 billion per year affair. From the Business Network [here]:

California wine industry has $51.8 billion impact on state economy, Wines and Vines,  Jan, 2007

The California wine industry has an annual impact of $51.8 billion on the state’s economy and an economic impact of $103 billion on the U.S. economy, according to a report released on Dec. 7 by Wine Institute (WI) and the California Association of Winegrape Growers (CAWG). The two organizations commissioned MKF Research, LLC to prepare the study, which was based on 2005 figures.

It is not yet known what the economic impact is of wildfire smoke on the 2008 winegrape crop. What is known is that smoke can taint the taste of wine, adding a tinge of “ashtray” flavor.

The Australian Broadcast Co reported last March [here] on a new study of wildfire smoke effects on in Aussie winegrapes:

Smoke taints wine grapes

ABC Rural, Tuesday, 18/03/2008

A world-first scientific study, conducted by the Department of Agriculture in WA [Western Australia], has proved that smoke taints the taste of wine grapes.

Trials done as apart of the report exposed grape bunches to heavy smoke from burning straw.

An independent tasting panel then said it was 99.9 per cent confident the taste of wine from the grapes was lower in quality.

Report co-author Mark Gibberd of Curtin University says the paper confirms what many have suspected for a long time

“We now have a published report which enables us to clearly demonstrate that if grapes are exposed to smoke, then there is a risk that those grapes will develop a taint in the wine, which would be potentially conceivable by consumers.”

The Wine Business Monthly presented more information about that study in September [here]:

Smoke Taint in Western Australia

As Australia faces a warming climate with increasing bushfire incidences, the issue of smoke-derived taint in grapes and wine has become a regular occurrence. The losses caused by smoke taint vary from year-to-year due to the unpredictable nature of bushfire events.

Smoke taint in grapes and wine, as a consequence of grapevine exposure to smoke, has resulted in financial losses and decline in product quality for several wine producers in Western Australia. Fire events have created smoke taint damage to grapevines on numerous occasions and have affected winegrapes grown in the Perth Hills, Swan Districts, Blackwood Valley, Great Southern, Manjimup and Pemberton regions.

The Department of Agriculture and Food WA (DAFWA) and Curtin University of Technology initiated research into the effects of smoke on grapes and wine in 2005. A research program has been developed to solve some of the mysteries surrounding smoke taint and to provide management options to vignerons. …

Fruit from all field-based experiments of smoke application to grapevines has been made into wine. Wine sensory analysis techniques, such as difference tests, aroma detection thresholds and quantitative descriptive analysis, have been employed. Fruit and wine samples have been analyzed by gas chromatography mass spectrometry analysis by the AWRI for key smoke indicator compounds of guaiacol, 4-methylguaiacol, 4-ethylguaiacol, 4- ethylphenol, eugenol and furfural. …

Research results: Initial investigation by DAFWA and Curtin University has revealed that grape and grapevine exposure to smoke impacts the chemical composition and sensory properties of wine, leading to an apparent ’smoke taint’. This research has for the first time established a direct link between smoke and the  sensory qualities of wine. Sensory studies established a perceivable difference between smoked and unsmoked wines (Kennison et al. 2007; Kennison et al. 2008b).

ClimateWire (a subscription Internet news service) described the “sensory properties’:

Even the most hard-core oenophiles will find it hard to name the notes in wines affected by “smoke taint.” The effect has been described as wet ashtray, charred meat, burnt coffee or smoked salmon, and it’s present in a significant percentage of California’s wines this season, experts say.

Climate Wire also noted that:

Kay Bogart of the Department of Viticulture and Enology at the University of California, Davis, said smoke taint is particularly dangerous to farmers in that it “doesn’t show its ugly teeth until after fermentation. You’ve invested all that money in grapes and production, and you’ve got a wine that is pretty much irreversibly damaged,” she said.

The Wine Spectator notes [here] that:

Smoke Taint a Concern in Northern California Vineyards, September 30, 2008

Laboratory tests have confirmed that the chemicals from the smoke are still present in some grapes. “We have seen samples that show smoke taint,” said Jerome Lillis, a chemist at Vinquiry Laboratories in Windsor. While the samples have shown perceptible notes of taint above sensory threshold, Lillis cautioned that the methods of detection are still being validated. He also said that smoke taint has only appeared in a handful of wines so far.

That appears to be the case, as many vintners are reporting no signs of smoky grapes. Milla Handley, of Handley Cellars, who has been testing the grapes personally and sending samples to be lab tested, said that all the grapes coming through her winery have been clean. Even though the fruit doesn’t appear to be tainted, the winery will still be taking precautions. “[We’re] going to be a little more conservative in our winemaking techniques this year,” said Handley.

Whether or not smoke taint is an issue, many winemakers are taking steps to mitigate any possible effect on their wines. Drew is decreasing the maceration time of his grapes and using a shorter cold soak and a gentle punch down to limit the amount of contact the skins will have with the juice.

Winemakers outside of Mendocino County are less concerned with the issue. Monterey County and Lake County were also hit by wildfires but the grapegrowing areas appear to have been too far away from the fires for the smoke to cause a problem. “I have talked to several growers and winemakers and no one is aware of any smoke taint,” said Shannon Gunier, executive director of the Lake County Winegrape Commission.

It’s too early to tell what kind of effect the smoke taint may have on the finished wine. Paul Ardzrooni, who manages vineyards in Anderson Valley, said that since the taint is site specific, no generalizations can be made about the smoke’s overall effect. He also notes that while the concern exists, it has not kept winemakers from buying the grapes.

Winemakers will have to wait until spring when the wines are being bottled to see if the smoke taint is an issue. If any of the smokiness persists, some winemakers say they may look into taint-removal systems. “It may be a lot of worry over nothing or it could be a stamp of the vintage,” said Holstine.

Wine taint removal systems based on reverse osmosis (RO) have been touted [here], but some vintners believe that RO leaves a “scar” on the wine flavors [here]. RO also adds cost to a vintage that is sub-par (and priced accordingly). It’s an economic double-whammy.

The overall effect of summer-long smoke from USFS forest fires on the Cal wine industry is as yet unknown. What is known is that fire managers never considered the effect their smoke might have on this major segment of California agriculture. Nor did fire managers consider the effects of smoke from extended fires on public health, recreation, air pollution, or CO2-related climate change.

Had they taken those effects into account, they never would have allowed fires to burn for 3 to 4 months, the practice implemented this summer in California national forests including the Los Padres NF, Siskiyou NF, Klamath NF, Six Rivers NF, Shasta-Trinity NF, Sequoia NF, and others.

Let It Burn has side-effects that occur beyond the boundaries of our national forests. Besides the human health crises from respiratory distress, hundred billion dollar industries can be negatively impacted. The Cal wine industry might consider whether it is truly in their economic best interests to allow the USFS to Let It Burn with impunity.


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