Michel Pravikoff, from the Bordeaux-Gradignan centre for nuclear research, recently came across a few bottles of California red (Cabernet) and rosé (Grenache) wines from 2009 to 2012.
His curiosity led him to put them through radioactive measurement tests. The vintages fall either side of March 11, 2011, when the tsunami caused the nuclear accident at Fukushima. However, while many measures have been taken - the most alarming being tunas that had probably swum from Japan - the radioactivity of a wine had yet to be studied in America.
Despite this, around twenty years ago in France, work by Philippe Hubert showed the presence of Cesium-137 in Bordeaux wines. This can be explained by the atmospheric nuclear tests that took place between 1945 and 1975, and of course Chernobyl in 1986.
The isotope, occurring in quantities that are not hazardous for health but are sufficient to be detected, has even promoted the development of techniques to curb counterfeiting. Radioactivity decreases in a predictable way, and therefore by measuring it and comparing it to a standard, the vintage stated on the label can be tested for its authenticity. Of course, the dating can only be done for vintages after 1945, or conversely, to demonstrate that a wine is not pre-1945 if it contains radioactivity.
For Californian wines, the radioactivity was too low for the measurement to be performed without opening the bottles. The wine first had to be reduced to ashes to be measured. The results showed that there is a clear increase in radioactivity following the accident at the Fukushima power plant, despite the 8,000 km that separate it from California.
Unsurprisingly, red wine, which undergoes longer skin-contact maceration, contains more radioactivity than rosé.
By Alain Echalier