RESEARCHERS at a South Australian university have found promising new technology in the bid to find ways to overcome smoke taint in grapes.

Smoke taint is considered a serious issue for grape and wine producers around the world, and recent devastating bushfires in South Australia and interstate led to ruined and smoke-affected fruit, and total vineyard loss in some cases.

Lead researcher and author Professor Kerry Wilkinson from the University of Adelaide School of Agriculture, Food and Wine investigated the use of activated carbon (AC) fabric bags to prevent the uptake of smoke by grapes.

“These prevented more than 95 per cent of the aromatic compounds responsible for unpleasant smoky, ashy flavours associated with smoke taint from getting into grapes during exposure to smoke,” she said.

"Smoke taint occurs because volatile compounds present in smoke are absorbed by grapes when smoke from bushfires drifts into vineyards and lingers for prolonged periods of time.

“It can greatly alter the composition and sensory properties of wine, leading to unpleasant smoky, medicinal and burnt rubber aromas and flavours – and a drying, ashy aftertaste.”

In 2020, an estimated 4 per cent of Australian wine grapes were lost due to smoke taint from bushfires.

The study was initiated in California, by Sir Peter Michael, with the application of smoke to bunches of Mataro grapes, some of which were enclosed in bags made from different AC fabrics: felt, light cloth and heavy cloth.

Sensory analysis performed on the resulting wines found that wine made from grapes enclosed in AC fabrics could not be differentiated from control wine made from grapes not exposed to smoke.

Prof Wilkinson said some drawbacks to the strategy and application were found on a widespread basis.

“There are several shortcomings that we still need to overcome: first, the AC fabrics studied were prone to tearing and had to be handled carefully to avoid damage,” she explained.

“Also, labour cost (of) applying AC fabric bags to individual grape bunches on a commercial scale is prohibitively expensive and probably viable only for ultra-premium grapes at this stage.

“These results demonstrate proof-of-concept, and we now hope to develop a more functional, cost-effective application for use in commercial vineyards.

“Nevertheless, use of AC fabric offers the most promising vineyard-based strategy so far for overcoming the issue of smoke taint.

“It could address a problem that has become a blight for producers globally. Initial uptake of smoke volatiles by grapes would be preferable to other strategies that ameliorate smoke-tainted grapes or wine and which are associated with potential loss of desirable wine constituents.”

The study was published in the Australian Journal of Grape and Wine Research.