Smoke Taint

Grapevine exposure to wildfire smoke during the growing season (véraison through harvest is the most vulnerable period). Volatile phenols (guaiacol, 4-methylguaiacol) from smoke are absorbed through grape skins and bind to sugars as glycosides, which are later released during fermentation.

Ashy, campfire, burnt, or medicinal flavors that intensify over time. The glycoside-bound compounds are initially masked but release acrid smoky character as they hydrolyze. Reds are more affected than whites. The taint can persist and worsen during aging.

There is no reliable cure once grapes are tainted. Testing (GC-MS analysis for smoke markers) before harvest determines severity. Options include: early harvest, activated carbon treatment (strips flavor), or not making wine from affected fruit. Climate change is increasing wildfire frequency.