Spanish blue wine on sale in France

The quirk is that the wine in question is blue – which has proven a hit with French consumers.

Vindigo – a word-play on 'indigo' and vino – contains no artificial colouring, but instead is filtered through red grape-skin pulp which turns it purpley-bluish.

The grape skin naturally contains a colourant known as anthocyanins, also found in forest fruits and black beans.

Vindigo is described by distributors in France as 'perfect for summer', since its relatively low alcohol level – 11% - means it does not dehydrate so much, and its flavour is said to be 'fruity' with notes of passion fruit, blackberry and cherry.

At present, in France, Indigo can only be bought from René Le Bail's wine merchant's in the south-eastern harbour town of Sète – and he has bought a batch of 35,000 bottles for retail nationwide, at prices typically ranging from €12 to €18.

Vindigo follows on from an earlier blue wine manufactured in Spain, which only lasted three days on the shelves but can still be bought online.

Gïk, created by a Basque-based start-up of the same name, was unable to be retailed in France since it did not comply with consumer rules.

Labels were only in English and Spanish, not in French, and it was not clear enough on the description how it had turned blue or what ingredients or processes had been included.