Jenna Fryer* and Elizabeth Tomasino
*Oregon State University, 100 Weigand Hall, Corvallis, OR, 97331 
(jenna.fryer@oregonstate.edu)

With the prevalence of wildfires in wine regions around the world, the flavor profile of wines has been negatively affected, causing an uncharacteristic “ashy” flavor. Smoke that reaches a vineyard transfers volatile compounds from the smoke into the grape. This then leads to wine with smokey, burnt, and dirty aromas, along with a unique ashy finish. All these descriptors are considered detrimental to quality. Although previously thought to be caused by volatile phenols found in wood fire smoke, recently a new class of compounds has been found to be a main causative agent. Thiophenols have been found in elevated levels in smoke-affected wines that, when in combination with the smoke phenols, lead to smokey and ashy flavors. There is no sensory threshold information currently available for thiophenols in wine. The goal of this work is to determine at what concentrations of thiophenols and phenols when present in Pinot noir, the wine is considered “ashy”. Using an adaptive staircase procedure with a yes-no paradigm, the recognition threshold levels of thiophenols and phenols were determined. In addition to determining the threshold level of these compounds, this work investigated potential differences in individual recognition sensitivity to these compounds. Previous work reported that there is a section of the population that is unable to perceive smoke-related attributes in wine and that those who do perceive them, have varying sensitivities. To understand further these varying sensitivities to smoke-related flavors, additional demographic and food consumption information was collected to determine whether threshold clusters arise based on these factors. With wildfires becoming more frequent, this research can be used to determine economic thresholds for wine production and targets for risk decision making. 

Funding Support: USDA-NIFA-SCRI, USDA-ARS