Radioactive carbon dioxide can help detect vintage fraud, Australian scientists say.
In a study presented to the American Chemical Society meeting in San Francisco this week, Dr Graham Jones of the University of Adelaide showed that measuring the amount of C-14 – or radiocarbon – in a wine can help determine whether it is really from the vintage stated on the label.
Between the 1940s and 1960s, atomic testing released C-14 into the atmosphere, which has since been diluted by CO2 from burning fossil fuels.
Other events such as the 1986 Chernobyl disaster also contributed to the level of C-14 in the background.
Grapevines have absorbed some of the C14, and their fruit – when transformed into wine – contains the same age ‘fingerprint’ as the vines.
Using an accelerator mass spectrometer, analysts can measure the radioactive element against the more common Carbon 12 – and compare it against a benchmark – to reveal the wine’s age up to within a few months, according to Dr Jones.
The method was tested on 20 Australian red wines made between 1958 and 1997 and found accurate to within a year.
The test works on the same general principle as one developed by scientists at the French national research centres in Bordeaux. The latter measures the presence of Caesium 137 (Cs137) to age-date wine.
‘Our technique may be slightly less precise,’ French scientists Philippe Hubert and Hervé Guégan said, ‘but ours works without having to open the wine. We have used it a lot on old bottles of Pétrus, Mouton, Romanée Conti, Yquem and Lafite supposedly from before 1950, to see whether there is any Cs137 – which would mean they are fakes. Some of them were.’
This test, along with PIXE (Particle Induced X-ray Emission) is used by vintage wine specialists the Antique Wine Company to authenticate both wine and bottles, to check whether they have been refilled with younger wine.
Written by Maggie Rosen