Producers understate true strength of wines

The rise of mighty merlots, stonking sauvignons and potent pinots has been a defining feature of our recent love affair with wine. And as the taste has got ever bigger so too has the amount of alcohol in our glass. Now new research has revealed that the modern breed of stronger wines is even more powerful than is claimed on the label.

A study carried out by a group of academics for the American Association of Wine Economists found that growers routinely and knowingly understated the alcoholic content of their wine in order to appeal to consumers' tastes for "more intense, riper flavours". With some brands now boasting 15 or even 16 per cent alcohol by volume, varieties from New World producers in Australasia and the Americas – where the hotter climate produces stronger wines – had to mark down their product further to make it appear weaker compared to European wines.

The authors found that label claims on average understated the true alcohol content of Old World wines from traditional producers in Europe by 0.39 per cent. New World wines were often understated by an average of 0.45 per cent, it was claimed. Each extra percentage point of alcohol in a drink corresponds to an additional 0.8 units per bottle – the equivalent of 20 per cent of the recommended safe drinking daily levels for men.

Based on more than 90,000 samples taken between 1992 and 2009 by the Liquor Control Board of Ontario, the report concluded that the phenomenon was a product of the drive for a bigger taste. It said errors in labelling were "not made unconsciously". It added: "This speculation is based in part on informal discussions with some winemakers who have admitted they deliberately chose to understate the alcoholic content on a wine label, within the range of error permitted by the law, because they knew it would be advantageous for marketing the wine."

Guy Woodward, editor of Decanter magazine said it was right for drinkers to be cautious about label claims, particularly when drinking North American wines.

Gavin Partington of the Wine and Spirit Trade Association said he did not recognise the description of drinking tastes in Britain. "The trend is towards lighter and refreshing drinks and away from those heavier styles," he said.