Australia — SMOKE taint caused by bushfires and fuel reduction burns can pose a serious threat to Victorias grape and wine industries, but very little is known about smoke uptake and accumulation in grapes.
Scientists from the Victorian Department of Primary Industries (DPI) have been investigating the link between smoke and wine quality with the aim to develop a web-based risk assessment tool to help growers determine the potential risk of smoke taint in grapes and wine.
DPIs research is now being expanded thanks to a $4 million allocation in the 2011 Victorian State Budget to establish a Centre for Expertise in Smoke Taint Research, based at Mildura.
The Centre will be home to a comprehensive research and development program that will significantly improve the industrys knowledge of how smoke impacts on wine and how to mitigate the risk of smoke taint.
Centre Director Dr Mark Downey said the bushfires in Victoria in 2007 and 2009 highlighted the devastating effect bushfire smoke could have on the wine industry.
Many vineyards in North East Victoria had fruit rejected, or the wine was made only to discover it was tainted and had no commercial value, Dr Downey said.
Low consumer appeal, due to smoke taint aroma, resulted in a $300 million loss to the wine grape industry.
Such a massive economic loss meant finding out when grapes are sensitive to smoke exposure and how management options can mitigate the negative effects of smoke became extremely important to growers and the industry.
Centre for Expertise in Smoke Taint Research Senior Research Scientist Dr Davinder Singh said an analytical method was required to enable researchers to detect compounds in wines and fruit associated with smoke taint.
We collected Chardonnay, Merlot, Shiraz, Sangiovese and Cabernet Sauvignon fruit from Victorias King Valley wine region following the 2006 and 2007 bushfires and developed an analytical tool in our Mildura laboratory to routinely measure levels of taint, Dr Singh said.
The major advantage of this method was its ability to measure both free and bound forms of taint compounds.
This was a significant achievement, not only in determining the extent of smoke exposure but also the source of high levels of taint identified during or after winemaking when taint compounds had not previously been detected, or were detected only low levels in the fruit.
For wine makers and consumers, this means smoke taint may increase in ageing wines, causing negative implications for the shelf life of bottled wines made from smoke exposed fruits.
In the event of another bushfire, these techniques can be used to determine a smoke index in the fruit and wines, which could help winemakers determine which fruit will be rejected or accepted by the market.
However, a comprehensive investigation is still required to determine at which stages different cultivars are more sensitive to smoke and to establish the impact of intensity and duration of smoke on taint levels in wine grapes.
This will also allow a timeline for prescribed burns to reduce the fuel and risk of bushfires.
These findings are a result of a collaborative effort between DPI, Curtin University, the Western Australia Department of Agriculture and The University of Adelaide.
The results of these findings have been published as two articles in the special issue of Australian Journal of Grape and Wine Research, 2011.