New technology can help wine producers monitor smoke taint

A smoke sensor developed by La Trobe University researchers has the potential to save hundreds of millions of dollars in lost wine production.

The sensors are in the process of being rolled out across the wine industry, with monitors now being used to track the impact of bushfires that have ravaged the Grampians.

Wine Industry Smoke Detectors (WISDs) – colloquially known as ‘wizards’ – track smoke events like bushfires and burn offs around vineyards and can advise winegrowers whether it is likely to taint their grapes; and if they need to discard their season’s harvest, or use winemaking techniques to remove the taint.

Data taken during trials of the sensor through the 2020 bushfires that devastated wine regions across Australia’s east coast found that $100-$150 million worth of grapes were needlessly discarded over unfounded concerns they were tainted by smoke.

Australian agri tech provider Goanna Ag has now signed on to commercialise the WISDs over the next two years, during which time the hardware and algorithms will be further validated by real-world fire events and the network of WISDs expanded to other wine regions across Australia.

Professor Ian Porter, a researcher from the School of Agriculture, Biomedicine and Environment at La Trobe, leads the team that developed the WISDs and the risk model over the last decade.

He said trials of their sensor in vineyards across south-eastern Australia had found that smoke did not taint wine grapes as much as viticulturalists had believed.

He said this meant vineyards could avoid significant losses of grapes that winegrowers had previously believed were ruined.

“Growers think that all smoke causes smoke taint, but data collected by our team has for the first time globally linked the amount of fresh smoke needed in vineyards to smoke taint in the bottle," he said.

"This has been the Holy Grail of research that’s now being solved.

“This sensor has the potential to save a heap of grapes they would usually throw away, which can be financially and emotionally devastating for winegrowers. It’s one of the reasons we developed the WISDs.”

The prototype smoke loggers have been developed by La Trobe University researchers supported with funding from Wine Australia, La Trobe itself and other partners, including the Victorian and Australian governments and regional wine associations.

A network of 100 prototype loggers was deployed in vineyards in north-east Victoria after the catastrophic bushfires in 2020, with the technology refined in the years that followed.

Operating like the networks that continuously monitor air quality for human health, the data loggers calculate risk ratings for smoke taint drawn from a vast database of smoke, grapes and wine data collected by La Trobe during more than 70 controlled burns and eight major bushfires.

This knowledge links smoke dose to smoke composition, phenol levels in grapes and wine and their sensory outcomes in wines. It also incorporates the critical risk factors for smoke taint, including burn conditions, distance from the burn, grapevine variety and the timing of exposure during the season.

Goanna Ag Winegrape Business Development Lead Jock Ferguson said they had a track record of working with proven science to help growers solve genuine, well-recognised challenges.

“We are particularly excited to be involved in the commercialisation of the WISDs. They are a vital industry breakthrough with appeal to stakeholders throughout the grape and wine sector in Australia as well as winegrowing regions around the world,” Ferguson said.

Professor Porter said their findings also showed that in the vast majority of cases, winegrowers need not be concerned that smoke form planned controlled burns to reduce fire risk might taint their grapes.

“The WISD is an amazing breakthrough for Australian growers and wine producers. It provides the sector with an extremely valuable tool to use during any smoke event to determine whether there is a problem or not”, he said.

“Having results in real time greatly reduces stress for growers and winemakers and allows them to market their grapes and produce wine with confidence.”

Researchers working on a solution to vineyard smoke taint

Smoke taint is a growing threat to vineyards around the world.

Bushfires, also known as wild fires, are more and more common given the onset of global warming and smoke taint from fires can ruin a vintage in a day or two.

Now researchers from Oregon State University have developed a special spray-on coating that they believe could protect grapes from being affected by wildfire smoke, the Drinks Business website reports.

The researchers expect to have a spray coating to prevent smoke damage available in the next several years.

“Wildfire smoke is an increasing problem for wineries in the United States and around the world and right now vineyard managers really have no tools to manage the effects of the smoke,” said Elizabeth Tomasino, an associate professor of enology at Oregon State. “This coating has the potential to transform the wine industry.”

Smoke taint has been a particular issue in Oregon and other parts of the western US, where recent vintages, especially that of 2020, were ruined by smoke from fires. It has also been an issue in Europe and Australia.

A new study, which was published in the Journal of Agricultural and Food Chemistry and funded by the Oregon Department of Agriculture Specialty Crop Block Grant and the US Department of Agriculture Specialty Crop Grant, examined how compounds caused by fires can be counteracted.

A cellulose nanofibre-based coating, containing chitosan and beta-cyclodextrin, was tested for effectiveness over two years at Oregon State University’s Woodhall Vineyard and its Southern Oregon Research and Extension Centre.

The researchers found that it successfully blocked compounds such as guaicol and syringol, while capturing meta-cresol. The distinction is crucial as blocking the compounds means that they are not absorbed (whereas capturing means they are).

Yanyun Zhao, an expert on food coatings, explained: “Not having to wash it off saves time, money and water for grape growers. That is what we are aiming for.”

Importantly, the study claims that the addition of the coating had no impact on the growth or quality of the grapes, meaning that the fruit’s aromas and phenols ripened as normal.

“Growers want something they can spray on their vines to protect them so if this becomes a commercially available thing it’s going to be a big game-changer," said Alexander Levin, director of the Southern Oregon Research and Extension Centre.

A press release from the university revealed that the research team is continuing to refine the coating, and working on a cost analysis to determine the viability of it as a solution for producers to deploy in the vineyard.

Relief for Bordeaux vignerons

Vignerons in Bordeaux are relieved that the region's vineyards appear to have avoided smoke taint damage despite recent wildfires (above) in the region. 

A conference organised by the Union of Oenologists of France at the Institute of Vine and Wine Sciences (ISVV) heard the news was positive. 

"We winegrowers, we are absolutely not worried," said Dominique Guignard, the president of the AOC Graves appellation. 

"In the vineyard there is no there is no concern, we have a vintage that promises to be exceptional,” he was reported as saying by the Vitisphere industry website. 

There were fires in July and August in the South Gironde including Landiras, which borders Graves and Sauternes. 

Guignard said smoke odours were rapidly dissipated by strong winds. 

“Today, from an analytical point of view, we are very confident about the harvest to come,” said  Vincent Renouf, general manager of Excell laboratories, based in Floirac, who said almost 400 analyses had proven negative to smoke taint. 

"To date, and there is no reason for this to change, we have very reassuring data on the potential organoleptic effects of fires on Bordeaux wines," he said. 

An important message from winemakers in Tasmania

Tasmanian wine producers have issued a plea to neighbouring farmers and forestry operators: Please don't ruin our vintage.

With the 2022 Tasmanian wine grape harvest well underway, Wine Tasmania has issued an urgent reminder of the potential devastating impact smoke can have on vineyards.

Vineyards are particularly susceptible to smoke exposure, which can cause irreparable damage to grapes and destroy the livelihood of the island’s wine producers.

Wine Tasmania CEO Sheralee Davies said that wine grape growers have worked tirelessly over the past year to manage their vineyards up to harvest time. Consequently, the remaining harvest period through to the end of May is crucial.

“It has been a challenging and varied season, commencing with unseasonably cooler weather in spring, which is causing a delayed harvest," Davies told a press conference at Pooley Wines (top). 

"Pleasingly, early reports of wine quality are positive, with overall wine volumes likely to be on par with the long-term average.

“One of the greatest concerns for wine producers at this time of the year is the potential impact of smoke from nearby fires. We encourage anyone planning to light a fire on their property in the weeks ahead to consult with nearby vineyards before igniting their burn to ensure they don't inadvertently cause major damage.

“Smoke can travel some distance from a fire and still cause damage to vineyards, and a short postponement of a fire may be all that is needed to prevent irreparable damage to this year's vintage.”

Land holders can get in touch directly with nearby vineyards to discuss proposed timing, the vineyard’s progress on harvesting and potential risks. They can also contact Wine Tasmania on (03) 6223 3770 for further information.

“The Tasmanian wine sector is building the island’s global reputation for its wines and encouraging visitation to its regional cellar doors," Davies says. 

"There is strong demand for our sparkling wines, pinot noir, chardonnay and more, and the 2022 vintage looks like being another great one!”

A brilliant use for smoke-tainted wine grapes

There is a new reason to visit the Meerea Park cellar door in the Hunter Valley.

The Eather brothers are well known for their aged semillons and cellar-worthy shirazes, as well as other wines including chardonnay, a marsanne-roussanne blend and even a pinot noir. 

A recent newcomer to the Meerea Park arsenal, however, is the India Finger Lime Gin, made for Meerea Park by Mobius Distilling using Hunter-grown wine grapes from the 2020 vintage and native finger limes grown by a family friend from Grafton in the north of New South Wales.

The wine used was smoke-tainted and not suitable for release, but proved ideal for distilling.

Other botanicals used in the gin include coriander seed, angelica root, liquorice root, native pepperberry, rainforest lime and orris root. A spirit for lovers of dry rieslings.

The gin is vegan friendly and extremely palatable on its own, as well as enjoyed with tonic and a slice of lime.

The Indie Finger Lime Gin costs $80 at cellar door or through the website at www.meereapark.com.au/wine/indie-finger-lime-gin/20254