Wildfire smoke contains hundreds of different volatile compounds. When grapevines are exposed to smoke, many of these compounds can accumulate in the grape berries. The volatile compounds are transported into the grapevine primarily through the waxy cuticle of the grape berry and through the leaves.
Of all of the compounds present in smoke, the volatile phenols guaiacol, 4-methylguaiacol, 4-ethylguaiacol, 4-ethylphenol, eugeneol, o-cresol, p-cresol, furfural and syringol are thought to have the largest impact on wine sensory qualities.