Wine Arcana

Concept

Smoke taint

Smoke taint is an unwanted sensory effect in wine associated with grapes exposed to smoke. It can appear as smoky, burnt, medicinal, or lingering ashy character. Exposure, measurable smoke compounds, and perceptible taint are related but distinct: smoke-exposed grapes do not invariably produce a wine that tastes smoky.

From smoke to grapes and wine

Burning wood releases volatile phenols, including guaiacol and cresols. Grapes can absorb these compounds and attach sugars to them, forming glycosides. These bound forms have little smoky aroma, making smell alone an incomplete assessment of the fruit.

Fermentation can release volatile phenols from some glycosides. Release in the mouth also contributes to the lingering sensation encountered when tasting an affected wine. Grape variety, developmental stage, smoke composition, and the duration of exposure change the risk.

Smoke taint therefore involves compounds inside the fruit, not just material resting on its surface. Analysis needs to consider both free volatile phenols and their bound forms.

Assessing the crop

The Australian Wine Research Institute (AWRI) uses background measurements from non-smoke-exposed grapes and wines to help interpret smoke-marker results. Some of these compounds can occur at low levels without smoke exposure. The laboratory method and the comparison dataset need to match.

Small-lot fermentation and sensory assessment supply another kind of evidence: how the fruit behaves when made into wine. A grower and cellar can use the combined information to decide which parcels to pick and how to handle them. A single marker concentration cannot establish the same sensory outcome for every grape and wine style.

Handling and treatment

AWRI's practical guidance describes keeping fruit cool and intact, excluding leaves, limiting skin contact, and separating press fractions to reduce extraction of smoke-related material. These options are easier to apply to promptly pressed whites than to a red wine whose colour and structure depend on skin fermentation.

Fining with activated carbon can remove some compounds, while also changing desirable aroma and other wine components. Filtration and other treatments require trials to establish their effect. Such operations can reduce impact in some wines but do not guarantee elimination of the problem.

What bottle age changes

A 2025 study followed forty-nine wines made from grapes exposed to wildfire smoke. Most measured phenols and glycosides remained stable over thirty-nine months. Some mildly affected wines became perceptibly smoky later, probably because other aromas had ceased to mask the smoke character.1. Mango Parker et al. (2025), abstract consulted. The study reports stability for most compounds, with syringol as an exception.

The finding separates a change in perception from an assumed continuing release of large amounts of smoke compounds during storage. It also helps explain why a young tasting and bottle-ageing assessment can give different impressions.

Sources