Wine Compound Interactions That Cause Perceived Smoke Taint in Red Wines.

Objective 1:  Evaluate and select Pinot noir and Cabernet Sauvignon wines that contain various levels of smoke taint.

As detailed in the previous years report more than 120 wines were collected that have various levels of smoke taint. The majority of wines (~100) were Cabernet Sauvignon and Pinot noir, but a few other varietals were also included such as Petit Verdot, Merlot and Syrah. Sensory analysis for these wines were completed in August 2023. We spent 9 months, running weekly sensory panels. This was longer than anticipated but we managed to collect a significant number of smoke impacted wines and did not want to miss the opportunity for larger data set, which can result in stronger causation in the last objective. At the start of each term panelists went through training and they also had retraining after 5 weeks, half way through the 10 week school term. The sensory protocol that was used can be found in Fryer and Tomasino (2022).

Objective 2:  Measure the volatile and nonvolatile chemical composition of the wines from Objective 1.

Measurement of volatile compounds are in progress. We are about half way done with this analysis. The protocol for volatile analysis was adapted from Zhang et al. 2023. We are about 3 months behind on the chemical analysis due to an installation delay with the liquid nitrogen tank used to provide gas to the equeipment and several compounds (utilized as chemical standards) that were back ordered. As of December 2023 analysis was able to recommence. Now that the sample prep for measuring smoke compounds (free volatiles, bound compounds and thiophenols) have been completed the student has started prepping for nonvolatile analysis at the start of January 2023. Free smoke phenols are being measured according to Liu et al. (2020) and bound smoke glycosides according to Caffrey et al. (2019). We are in the process of developing the method to measure the smoke thiophenols. The timeline in the 3rd year grant has been updated to reflect this change in timeline.

Objective 3:  Determine the chemical interactions causing smoke taint perception in Pinot noir and Cabernet Sauvignon wines using fsQCA – this will commence once chemical testing is completed.

Objective 4:  Validate results for fsQGCA using sensory testing – this will commence once chemical testing is completed.