Electronic nose can pinpoint where wine was made

It uses an electronic nose to make even the most confident sommelier a little nervous.

The technique exploits the unique and complex mix of thousands of compounds found in each bottle of wine that gives the drink subtly different scents and flavours.

Wine experts use the odour and taste of some of these compounds to identify types and vintages of wines during tasting sessions.

But the researchers have gone one step further and say they can pinpoint where a wine was made and even which barrel it was fermented in.

Using a kind of electronic nose, known as a mass spectrometer, they analysed the compounds in vaporised samples of wine to produce detailed chemical signatures that can be matched against a database of characteristics to identify a wine's source.

It means they can tell exactly which variety of grape a wine is made from, the region and vineyard where it was produced and the source of the wood used in the barrel.

They now hope their system can be developed to help fight trade in fake vintage wines which plagues the £ 100 million a year international fine wine trade.

Regis Gougeon, from the University of Bourgogne, in Dijon, France, who led the research, said: "In winemaking, several processes can subtly modulate the characteristics of wine.

"Wine experts use their eyes, mouth and nose as detectors and are able to distinguish wines according to their ages, grape varieties, terroirs.

"All we know is that so far, none of the sensory analyses of the wines we looked at could discriminate like we did.

"Our approach reveals the extremely high yet unknown chemical diversity of wine. It was exciting to be able to observe such a diversity at once, where many compounds, even in low concentration, may contribute to the body of the wine."

The flavour and aroma of a wine is influenced by a range of factors from the grapes used, the soil they were grown in, the climate at the time, the yeasts that aided the fermenting process and the wood used to make the barrels the wine was aged in.

As each forest has its own soil characteristics and mixture of lichens and parasites, the chemicals that seep into wine will vary depending on where the timber used in the barrels grew.

Until now scientists have focused on a narrow band of chemicals that could give them information about a wine's age or variety of grape.

But the researchers found that by analysing the entire mix of compounds on a sample of wine, they could obtain distinct signatures that can be used to trace a wine's history.

They analysed 48 samples from four different French wine and compared the signatures to the compounds found in wood from nine French forests used to make the ageing barrels.

Using information about the lichen growth and climate which leave chemical markers in the barrel wood, they were could also infer information about the age of the barrels the wine was kept in.

This could prove invaluable in proving the age of a wine as if it has been kept in barrels that are younger than the claimed vintage of the wine, it must be a counterfeit.

Telegraph.co.uk

By Richard Gray, Science Correspondent