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A chilled glass of Pinot Grigio or Chardonnay may look white, but has more in common with red wine than you might imagine.

Scientists have discovered that white grapes contain the same pigments that give red wine its colour, suggesting that 'white' wine may not really exist.

The presence of the pigments, called anthocyanins could explain why producers of white wine using white grapes are sometimes surprised to see a pinkish tinge in bottles.

Scientists have discovered that white grapes contain the same pigments that give red wine its colour. Called anthocyanins, they may explain why producers of wine using white grapes are sometimes surprised to see a pinkish tinge in bottles

Anthocyanins originate from the skins of grapes and combined with other chemical compounds, are responsible for the majority of red wine's colour.

The precise colour of red wine is dependent on the acidity surrounding anthocyanins in wine and in alkaline solutions, they give a blue colour.

Until now, most wine experts believed that white grapes didn't have anthocyanins in them, explaining why white wine is almost clear, Panagiotis Arapitsas of Italy's Edmund Mach Foundation told New Scientist. 

Anthocyanins originate from the skins of grapes(Chardonnay are pictured) and combined with other chemical compounds, are responsible for the majority of red wine's colour

But using mass spectrometry to analyse Chardonnay, Sauvignon Blanc and Riesling grapes, which are used to make white wine, his team discovered that these grapes so in fact contain anthocyanins.

The concentrations of anthocyanins found in white grapes are several thousand times smaller than in red grape varieties such as Merlot, according to the study, published in Food Research International.

Mr Arapitsas believes that the discovery may explain the long-standing mystery of why wine producers sometimes end up with white wine that looks pink like rosé.

Anthocyanins are known to give blackberries and raspberries their colour, as well as autumn leaves, according to Bournemouth-based Andy Brunning, who writes the blog Compound Interest,

He explained that red wine is a complex mixture of between 800 and 1,000 chemical compounds. 

Compounds called tannins and phenolics make up just 0.1 per cent of a bottles of red wine, but have the biggest impact on its colour and flavour.

'As wines age, molecules of anthocyanins can undergo a wide variety of reactions to form larger "complexes", which can also contribute to the red colouration of the wine,' Mr Brunning explained.

'As a result, although the concentration of anthocyanins in a bottle of wine will constantly decrease... the red colour will still remain.'

Tannins - small molecules joined together to make a long chain - dictate a wine's 'dryness' and bitterness, reacting with the proteins of a drinker's saliva to create the sensation of dryness.

They can also contribute to the colour by combining with the anthocyanins.

Anthocyanins, which were previously only thought to be found in red grapes, are known to give blackberries and raspberries their colour, as well as autumn leaves (pictured)