Thinking Inside the Box: A Novel Approach to Smoke Taint Mitigation Trials

Abstract

When bushfires occur near wine regions, grapevine exposure to smoke can taint grapes due to the uptake of smoke-derived volatile compounds that can subsequently impart unpleasant smoky, medicinal, burnt rubber and ashy characters to wine. Whereas early research sought to understand the effects of smoke on grapevine physiology, and grape and wine chemistry, research efforts have shifted towards the strategic imperative for effective mitigation strategies. This study evaluated the extent to which excised grape bunches could be reproducibly tainted during smoke exposure in a purpose-built ‘smoke box’. The volatile phenol composition of grapes exposed to smoke for 30 min was similar to that of smoke-affected grapes from field trials involving grapevine exposure to smoke. Some variation was observed between replicate smoke treatments, but implementing appropriate controls and experimental replication enabled the smoke box to be used to successfully evaluate the efficacy of several agrochemical sprays and protective coverings as methods for mitigating the smoke exposure of grapes. Whereas the agrochemical sprays did not provide effective protection from smoke, enclosing grape bunches in activated carbon fabric prevented the uptake of up to 98% of the smoke-derived volatile phenols observed in smoke-affected grapes. As such, the study demonstrated not only a convenient, efficient approach to smoke taint research that overcomes the constraints associated with vineyard-based field trials, but also a promising new strategy for preventing smoke taint.

The Effect of Pre-Veraison Smoke Exposure of Grapes on Phenolic Compounds and Smoky Flavour in Wine

“…Te concentration of these seven volatile phenols and six glycosides has been determined in over 1,000 samples of non-smoke exposed grapes and wine of twelve major cultivars produced in Australia and can be used to identify samples suspected of smoke exposure [10]. Te concentrations of all seven volatile phenols and six glycosides need to be considered when assessing smoke exposed grapes, as they can be present in varying proportions: typically SyGG is the most abundant marker for smoke exposure of grapes and volatile phenols are present in low concentrations, but patterns such as elevated volatile phenols and low concentrations of glycosides have also been observed in some samples [11].…”

Amelioration of Smoke Taint in Wine via Addition of Molecularly Imprinted Polymers during or after Fermentation

“…Semillon and Merlot grapes were again sourced from vineyards located at the University of Adelaide's Waite Campus (when TSS were 19 ± 1 °Brix, respectively); however, smoke treatments were applied postharvest using a purpose-built smoke box. 34 Briefly, grape bunches (∼3 kg per replicate per treatment) were suspended on racks in the smoke box (0.8 × 0.8 × 1.5 m), and smoke was generated by combusting barley straw (100 g) in a commercial fire box smoker. The duration of smoke exposure was 15 min, starting when smoke was first observed in the smoke box.…”

Facing post crisis challenges through leadership and inclusion: The case of Napa Valley

“…En l'état, Napa traversait une conjoncture similaire à celles des autres régions du monde, mais il fallait rajouter à cela les conséquences dramatiques des incendies de 2020. Ils avaient détruit certains vignobles intégralement et affecté irrémédiablement 80 % de la production des vins de Napa pour ce millésime à cause des effets des fumées sur le raisin (11).…”