Final Report: This is a completed project for the Washington Grape & Wine Research Program
Date: 2016-2019
Project Title: Assessing Smoke Taint Risk Based on the Composition of Smoke Exposed Grape Berries and the Resulting Wines
PI Name: Thomas Collins, PhD
CO-PI Name: Markus Keller, PhD
Cooperator Name: Jim Harbertson, PhD
(Dr. Harbertson’s team made the wines from the smoke taint trial, following agreed upon winemaking practices.)
Project Summary:
The exposure of vineyards to smoke from wildfires can result in wines which are described as smoke tainted or smoke affected. Affected wines exhibit off-aromas described as medicinal, smoked salmon, cold ash and similar, while descriptors of the aftertaste of affected wines include smoky and ashy, along with increased harshness in the finish (Parker, et al. 2012; Whiting and Krstic, 2007) Evaluations of forestry and other wildland management practices as well as climatic conditions suggest that wildfire outbreaks will continue to occur in close proximity to areas of viticultural importance and may be expect to increase in intensity as well (Westerling, et al. 2006). As smoke affected wines at best require additional processing to ameliorate the effects and in many cases, cannot be used even with additional processing (Fudge, et al. 2011; Fudge et al. 2012), methods for the assessment of the risk associated with smoke exposure for the resulting wines are needed. The proposed research will address that need by the deliberate exposure of research vineyards to smoke of similar intensity and duration as seen in recent wildfire episodes in Washington, along with the analysis of the chemical composition of the smoke exposed fruit and the wines made from that fruit. An evaluation of winemaking practices including minimization of skin contact and the use of enzymatic hydrolysis and reverse osmosis (RO) for smoke taint reduction will be an integral part of the proposed research. This proposal addresses the industry priority for smoke taint analysis and removal through careful characterization of both the affected fruit and the resulting wines.
Project Major Accomplishments:
The primary objectives for the first year of this study were as follows:
- Develop the methodology for the application of moderate levels of smoke over extended (2-10 day) periods.
- Analyze grape leaves and fruit for the presence of free and bound smoke related compounds in grapevines exposed to smoke in Objective 1.
- Monitor the extraction of smoke taint related compounds and their glycosides during and following the fermentation of fruit from grapevines exposed to smoke in Objective 1.
- Treat a subset of the smoke affected wines using reverse osmosis to reduce the concentration of smoke taint relate compounds and their glycosides. Monitor the treated wines for the release of glycosidically bound smoke taint related compounds post-treatment.
Read more by downloading the full report above.