Kerry Wilkinson* and Renata Ristic
*The University of Adelaide, PMB 1, Glen Osmond, 5064, Australia
(kerry.wilkinson@adelaide.edu.au)

Grape and wine producers around the world are searching for strategies to mitigate the negative effects of vineyard exposure to wildfire smoke (unpalatable smoky and ashy characters, which can render wine unsaleable), and which in recent years has led to revenue losses estimated at hundreds of millions of dollars. In the vineyard, various preventative measures have been evaluated, from washing smoke-affected grapes to applying protective sprays or coverings to vines prior to smoke exposure. In the winery, remedial treatments have included postharvest ozonation, limiting skin contact during fermentation, spinning cone column distillation of juice or wine, and the addition of adsorbent materials such as activated carbon (either directly, or in combination with nanofiltration). The transformation of smoke-tainted wine into beverage spirit via distillation has also been evaluated. This presentation will provide an objective assessment of the efficacy of different vineyard- and winery-based mitigation strategies, by comparing the concentrations of volatile phenols (in free and glycosylated forms) as chemical markers of smoke taint, alongside descriptive analysis of wine sensory profiles. Limitations associated with promising mitigation strategies and the potential for strategies to be applied in tandem will also be discussed. The compositional data also demonstrates how the natural occurrence of volatile phenols in the fruit of some grape cultivars, and the susceptibility of different volatile phenol glycosides to hydrolysis, can complicate evaluation of smoke taint mitigation strategies.

Funding Support: Wine Australia, The Australian Research Council, he University of Adelaide, Peter Michael winery, Australian State and Federal Governments