Grants and Contributions:

Grant or Award spanning more than one fiscal year. (2017-2018 to 2018-2019)

Ripening grapes exposed to forest fire smoke often yield wines that are characterized by an unpleasantx000D
smoky/ashy flavor (or aroma) that is unacceptable to consumers. This phenomenon, called smoke-taint, isx000D
increasingly problematic for Canada's vineyards and wineries since these are often located in regions prone tox000D
frequent, intense forest fires. Given the potential for significant financial losses due to smoke-tainted wines,x000D
there is an obvious need for risk assessment strategies that can accurately determine the intensity of smokyx000D
flavor in grapes before fermentation (and, ideally, harvest). Current testing methods employ an analyticalx000D
technique known as gas chromatography-mass spectrometry (GC-MS) to test for the presence of compoundsx000D
(like guaiacol) known to have a smoky flavor. Although several North American companies already providex000D
GC-MS-based smoke-taint tests, a major problem with these tests is that compounds like guaiacol are oftenx000D
stored in grapes linked to various sugars. These sugar-linked, smoke-flavoured compounds are neitherx000D
detectible by GC-MS nor are they easily perceptible by taste or smell, however, they maybe released by thex000D
yeast during fermentation and possibly ageing. Based on our knowledge of the regulation other flavourx000D
compounds in grapes/wines, it is hypothesized that the majority of smoke-flavoured compounds are storedx000D
within grapes as their sugar-linked analogues. We are proposing to develop procedures by which thex000D
sugar-linked smoke-flavoured compounds in grapes can be rapidly cleaved, without fermentation, to enablex000D
compounds like guaiacol to be detected by existing GC-MS methods. The conditions to effect such cleavagex000D
that have been reported in the literature published to date are not suitable to be used for accurate assessmentx000D
purposes. Our improved method will permit our company partner, Sebastian Farms (a vineyard in the Markx000D
Anthony Group) to assess the "smoke-aroma potential" of grapes before harvest, enabling insurance planning,x000D
and supporting the development of in-vineyard or in-winery mitigation strategies. The method will be fullyx000D
compatible with Sebastian's existing smoke-taint assessment providers and R&D facilities.