Researchers from Oregon State University are attempting to create a coating that will protect grapes in vineyards from the impact of wildfire smoke.

In a bid to avoid the so-called “off” taste of wine produced from grapes exposed to wildfire smoke, the researchers are attempting to develop a coating that can be applied to grapes in the vineyard by targeting three compounds called volatile phenols, which reportedly contribute to smoke taint in the fruit.

Pinot noir grapes at Oregon State University's Woodhall Vineyard undergoing smoke experiments. Source: Sean Nealon

The researchers created cellulose nanofiber-based coatings composed of chitosan and beta-cyclodextrin, which, depending upon their formulations, can block guaicol and syringol and capture meta-cresol — wildfire smoke compounds that give wine its “off” flavor when absorbed by wine grapes.

The researchers explained that the difference between blocking and capturing these compounds is important, wherein blocking suggests that the coating doesn't absorb the phenol compounds and, consequently, would not need to be washed off ahead of winemaking. Meanwhile, capturing suggests that the coating absorbs the compounds and subsequently would need to be washed off. The team is seeking to develop the former iteration where grape growers could simply wash off the coating.

In addition to developing a coating that easily washes off the grapes, the researchers are also attempting to overcome a challenge presented by the different chemical shapes of phenols, which makes it difficult to create a coating that appropriately adheres to different shapes, thereby making it challenging to block the smoke.

An article detailing the development of the coating, “Evaluation of Functional Spray Coatings for Mitigating the Uptake of Volatile Phenols by Pinot Noir Wine Grapes via Blocking, Absorption, and/or Adsorption,” appears in the Journal of Agricultural and Food Chemistry.