The technical abilities of critics more generally are also in question. Can they really spot all those unusual "notes" of tobacco, leather, cherry wood, toasted herbs and many more in a single sip of wine? A study in the journal of experimental psychology showed that it is hard to identify more than four components, yet critics regularly refer to many more. So in 2008, a retired professor of statistics from Humbolt University in the US decided to take a closer look.

Robert Hodgson, who went on to become a small wine-maker himself, discovered that the judges of the important California State Wine Fair in Sacramento struggled to reach the same conclusion tasting the same wine twice. He vetted up to 70 judges over three years, asking them to rate on a scale of 80 to 100 three samples of each wine poured from the same bottle. Only one in 10 of the judges could rate the same wine within two points, and typically varied by four points.

Last year, Hodgson analysed 2,440 wines in more US contests, and found 84% of gold medal winners in one contest won no medal in another. He concluded: "Many wines that are viewed as extraordinarily good at some competitions are viewed as below average in others." His verdict was that "winning a gold medal may be more a matter of chance than a predictor of quality".