Ever paid top dollar for a bottle of wine that says on the label it’s from a much-sought-after year, only to find that it tasted like cheap, non-vintage plonk?
Well, a team of researchers in Australia, who think “vintage fraud” is widespread, have come up with a test that uses radioactive carbon isotopes left in the atmosphere by atomic bomb tests last century and a method used to date prehistoric objects to determine what year a wine comes from, or its vintage.
The test works by comparing the amount of carbon-12 and carbon-14 in grapes.
Both are isotopes of carbon and are captured by the grape plants when they absorb carbon dioxide, the main nutrient used by living plants in their growth cycle.
Carbon-12 is the main isotope in the carbon absorbed by the grapevines, and is very stable, while only tiny amounts of carbon-14, a radioactive isotope, are found in the plant.
The amount of carbon-14 has varied over the years, too, which makes it a useful tool for judging the true age of a wine.