Study Finds Smoke Taint Can Move Through Grapevines

A study published in the journal Food Chemistry is adding new detail to one of the wine industry’s most persistent problems: smoke taint, the off-flavors that can appear in grapes and wine after wildfire exposure. The research examined whether volatile phenols from smoke can move inside grapevines from contaminated leaves to the fruit, a question that matters for growers trying to protect harvests in fire-prone regions.

The findings suggest that the issue may be more complicated than direct exposure of the berries alone. In experiments with grapevines exposed to smoke, researchers detected free and glycosylated volatile phenols in leaves and in fruit that had been exposed. But clusters protected with activated carbon fiber coverings did not accumulate the same taint markers, pointing to a possible role for internal transport within the plant rather than only surface contamination of the grapes.

That distinction could affect how vineyards respond when smoke drifts through growing regions. If compounds absorbed by leaves can later move into fruit, then protecting only the clusters may not be enough in some situations. The study supports preventive measures that address the whole vine, including activated carbon fiber covers, which may help reduce contamination during wildfire events.

Smoke taint has become a growing concern for wine producers as wildfires have become more frequent and more intense in many wine regions. The compounds linked to the problem are often measured as volatile phenols and their bound forms, which can later be released during fermentation or aging and create ashy, smoky or medicinal notes in wine. Growers and winemakers have long struggled with the fact that grapes can appear healthy at harvest while still carrying hidden smoke-related compounds.

The new research helps narrow down where those compounds may come from. By comparing leaves and fruit under different exposure conditions, the scientists found evidence consistent with movement of smoke-derived compounds through the vine. That does not mean every case of smoke exposure will lead to taint in fruit, but it does suggest that leaf contamination should be taken seriously when assessing vineyard risk after a fire.

For growers, the practical implications are immediate. Vineyard managers often have to decide quickly whether to harvest, discard or isolate fruit after smoke exposure. Better understanding of how volatile phenols travel inside the plant could improve those decisions and help reduce losses in seasons when wildfire smoke threatens production.