NOVEL BENZENETHIOLS WITH PHENOLS CAUSE ASHY, SMOKE FLAVOR PERCEPTION IN RED WINES

Abstract

Smoke impacts on wines are becoming a worldwide problem; the size and severity of wildfires increasing due to influences from changing climates.¹ For over a century, wines have been known to have a unique issue of absorbing chemical compounds derived from wildfire smoke wherein the flavor of the subsequent wine becomes ashy, rubbery, campfire-like, and smoky.² The economic impacts of a smoke-impacted wine can last for years depending on the grape varietal, costing Oregon and Washington states in the United States over a billion dollars from the 2020 wildfires, as an example.³ While years of research have indicated elevated concentrations of smoke-related compounds, such as guaiacol and syringol, in wines after smoke events, unfortunately, replicating the sensory experience using smoke-associated phenols has not had much success.⁴ In our study, we found elevated concentrations of benzenethiols in smoke-impacted wines. 13C-labelled smoke data suggests phenol conversion into benzenethiol. A follow-up sensory experiment showed that the ashy aftertaste of smoke-impacted wines can be replicated by adding elevated amounts of benzenethiols and phenols to a wine that was previously not influenced by smoke. The novel targets could lead to better fining methods to remove the unwanted benzenethiols to achieve the flavors and aromas desired by winemakers and consumers.