Stellenbosch boffins search for source of 'burnt rubber'

Researchers in South Africa have launched a hi-tech scientific investigation into the causes of the distinctive 'burnt rubber' aroma found in many of the country's red wines.

The University of Stellenbosch has joined forces with wine industry research body Winetech to undertake the research, which was initiated by Wines of South Africa (WOSA).

Wine writers from the UK in particular have long identified a distinctive aroma commonly found in South African wines, variously described as rubbery, burnt, smoky, green or dirty.

Beginning this month, the scientists will use an array of techniques, including microbiological and chemical analysis, infrared spectroscopy, as well as a gas-chromatography-olfactory analysis. No fixed timescale has yet been given to the research.

'We wanted to do something constructive to see if we could get a better understanding of what the aroma is and the cause of it,' said WOSA UK market manager Jo Mason.

The aim is to educate wine growers and producers, but not necessarily to completely eradicate the flavour. 'There's a large middle ground where there is a South African character which we're not looking to lose,' said Mason.

'We're not looking to create homogenous wines that could come from anywhere.'

Some commentators have suggested that the aroma might be caused by leaf-roll virus in South Africa's vineyards, but Mason questioned this.

'South African viticulturalists say they don't have a huge problem with it – and it's not unique to South Africa anyway,' she said.

Richard Woodard