Effect of smoke application to field-grown Merlot grapevines at key phenological growth stages on wine sensory and chemical properties

Abstract

Background and Aims: Smoke exposure of grapevines and development of smoke taint in wine are issues of increasing incidence and severity. There is limited understanding of the effect of phenological stage at the time of smoke exposure on taint development. The aim of this study was to demonstrate the variation in smoke uptake and taint development between and within seasons. Methods and Results:Smoke was applied to field-grown Merlot grapevines at 12 stages of vine development over three growing seasons. Key periods of vine sensitivity to smoke taint in wine were (i) from shoots at 10 cm to full bloom (low levels of smoke taint); (ii) from berries at pea size to the onset of veraison (variable levels of smoke taint); and (iii) between 7 days post-veraison and harvest (high levels of smoke taint). Conclusions:The severity of taint in wine varied depending on the phenological timing of grapevine smoke exposure. Taint was elevated when exposure occurred between 7 days post-veraison and harvest. The carry-over of smoke constituents the following season was not detectable in wine but yields were reduced. Significance of the Study: This is the first study to demonstrate the timing of smoke exposure to critically affect wine chemical and sensory characters. These effects were consistent and reproducible over three seasons.

Amelioration of smoke taint in wine by treatment with commercial fining agents

“…2009, Hayasaka et al. 2010a,b,c) and the influence of grapevine phenology on the extent of smoke taint in wine (Kennison et al. 2009, 2011).…”

Smoke taint compounds in wine: nature, origin, measurement and amelioration of affected wines

“…A peak of sensitivity occurring from 7 days post-veraison was confirmed. As for seasonal effects, no carryover of guaiacol or 4-methyl guaiacol was seen between seasons; however, yield appears to have been reduced within season by~24% and in the season following exposure bỹ 50% (Kennison et al 2011). Further research will determine if these effects on yield are reproducible.…”

“…Guaiacol was the predominant volatile phenol ranging from 0 to 100 mg/L for single treatments or a total of~400 mg/L for repeated exposure. In a recent report (Kennison et al 2011), smoke applied at 12 stages of development over three seasons revealed key periods of vine sensitivity to smoke taint in the wine. Thus, 'low' and 'variable' levels of taint were evident where exposure occurred from 'shoots at 10 cm to full bloom' and from 'pea size berries to onset of veraison', respectively.…”

“…Some of the most recent findings are included as a series of five papers , Kennison et al 2011) featured online (VSI link) and in the following pages.…”

Review of smoke taint in wine: smoke-derived volatile phenols and their glycosidic metabolites in grapes and vines as biomarkers for smoke exposure and their role in the sensory perception of smoke taint

“…In an extension to this study, smoke was applied to field‐grown Merlot grapevines at 12 stages of vine development over three growing seasons (Kennison et al. ). Differences in a vine's sensitivity to smoke taint in wine were observed among the different growth stages.…”