Efforts to create a spray-on coating that protects wine grapes from wildfire smoke taint have been boosted by promising recent test results in the laboratory and on Pinot Noir vineyards, according to scientists at Oregon State University.
It’s hoped a spray that can help prevent off-flavours in wine caused by smoke taint could be launched in the next few years, said researchers.
The team’s work was influenced by reports of significant damage to wine grape quality in parts of Oregon, California and Washington State following fierce wildfires in 2020.
‘Wildfire smoke is an increasing problem for wineries in the US 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.’
Recent tests by Oregon State University researchers have focused whether newly developed coatings can either capture or block three harmful smoke compounds known as volatile phenols.
In a study published in the Journal of Agricultural and Food Chemistry, researchers trialled different formulations of cellulose nanofibre-based coatings containing chitosan and beta-cyclodextrin.
These were developed by Yanyun Zhao, a professor who has studied food coatings for more than 20 years, and Jooyeoun Jung, a senior researcher assistant professor in Zhao’s lab.
Tomasino told Decanter: ‘While I don’t know the exact time line for this, we have made significant progress in the past three years, so I do see something available over the next few years, although there are several steps beyond creating the coating that have to occur.’
Tomasino added, ‘The next major research steps are working on the formulation so that it stops all the smoke compounds from getting to the grape. We are currently able to stop guaiacol, 4-methylguaiacol, syringol and 4-methylsyringol. We are working on stopping the cresols from getting through.’
Another important aspect of the work will be to determine it coatings need to be washed off prior to winemaking.
If the coating ‘blocks’ volatile phenols, then it may not need to be washed off, but if it ‘captures’ them then the whole coating might need to be removed before producers begin work in the cellar.
‘Not having to wash it off saves time, money and water for grape growers,’ Zhao said in an Oregon State University press statement. ‘That is what we are aiming for.’
Coatings have been tested in the University’s Woodhall Vineyard, with smoke chambers placed over vines, and wine from these grapes is being analysed, researchers added.
‘We know that the coatings do not impact ripening or any grape quality parameters and part of that next research is that if the coatings are not washed off, how would that impact wine quality,’ said Tomasino.
‘All the ingredients are food grade and the base coating has been approved by the FDA [US Food & Drug Administration] as food grade.’ However, a further regulatory check could be needed for the final formulation, which is yet to be determined.
