The chemicals in a Bloody Mary are 'highly unstable' - and its quality tends to deteriorate quickly because of the acids in the tomato juice, he said.

A mix of tomato juice and vodka, along with lemon or lime, horseradish, Tabasco and Worcestershire sauces, black pepper and celery salt, the Bloody Mary packs a punch.

Dr Neil da Costa, who presented his research on the Bloody Mary at a meeting of the American Chemical Society yesterday (TUE), said: 'It's a very complicated drink.