LONDON: The taste of some of the world's finest wines is changing as global warming alters the way grapes mature, scientists have found.

Grapes such as pinot noir, merlot and chardonnay are now growing more quickly, subtly changing the compounds produced as they ripen and the synchronisation between maximum flavour and the ratio of sugar to acid, scientists said.

An increasing number of vineyards are thus struggling to identify the perfect moment for picking the grapes to ensure their wines retain their characteristic flavours, according to research by Kimberly Nicholas, associate professor of sustainability science at Lund University in Sweden.

"Climate change is beginning to affect the singular flavours that people expect from different wines - the experience you come to know and trust from your favourite reds and whites," Nicholas said in a report published in the journal Scientific American.

"As a grape matures, its sugar level rises and its acid level falls. The ideal ratio for picking occurs at around four months. Overall flavour should also peak at that time, creating a tight window for the best harvest time," she said.

Climate change is making the identification of the harvest window more difficult, Nicholas was quoted as saying by 'The Times'.

"As the atmosphere warms, the desired ratio of acid to sugar occurs earlier in the season," she said.

"The optimal flavour moment may occur earlier too - but not as much - leaving a gap between the ideal sugar-to-acid ratio and the ideal flavour. Grapes may also ripen too fast to accumulate flavour or colour," she added.