Wine critics love them - those enormously muscular wines which flex themselves beyond the run of the mill in a line-up of a hundred samples. And it has long been a criticism of bulk tastings, that more delicate wines are lost against the ambient noise of production line wine judging. 'By all the definitions of table wines that I've found,' said Napa winemaker and consultant George Vierra recently, 'these wines are surely pretenders and can no longer find a place at the dinner table.' The preference of powerful wine critics such as Robert Parker for these blockbuster wines - which often weigh in with a massive 95 or more points out of 100 on the Wine Advocate scale - encourages an elitist preference for such wines. This drives an economic imperative through the market where other wineries will attempt to emulate the style in order to achieve acclaim and thus sales. In an article in Wine Business Monthly, Vierra said these wines should be called 'social' wines rather than 'table' wines as they completely inundated the flavour of even the most outgoing cuisine and were thus not appropriate to be served alongside food. The problem is this: even though they're not user friendly, making any wine in a climate driven haywire by global warming may not leave vintners with much of a choice. The best wines start with grapes that have matured on the vine in such a way that complete phenolic ripeness is achieved, where sugar develops, acid drops off a bit and natural flavour compounds round off the berry. Dr Greg Jones, associate professor of Southern Oregon University's Geography Department, said during a visit to the Cape recently that in the old days in the United States it was difficult to achieve optimum phenolic ripeness because of vine diseases. 'People were harvesting fruit with sugar levels of between twenty one to twenty three brixs and would only get eleven to twelve percent alcohol. We became accustomed to what we thought was proper ripeness. Because we've replanted with virus free material in Napa, the vine has a shortened ripening window so we're getting higher sugar levels and a different type of ripeness.' A changing climate is assisting the vines in achieving high sugar. Jones said the climate in Napa and Sonoma has become more conducive and far less risky for winemaking. 'There's almost no frost any more and the growing season is longer by forty or more days a year...' The result: wines with massive alcohol. This phenomenon is not limited to the Napa Valley. Scanning wine columns across the globe reveal the trend mostly from New World wines which have scribes nervous: two decades ago, wines of 11% alcohol were the norm; today it's bumped up to 14%. Writing on the subject, Jon Bonné talks about Turley Wine Cellars producing 'near-cult status Zinfandels in the 17% range' and '17.2% Garretson Wine Company Syrah'. Loftie Ellis, Elsenburg Agricultural College lecturer, has also noticed this trend but doesn't think the consumer will tolerate it. The problem is, as temperatures warm, consumers may have about as much of a choice in the matter as winemakers do. Anecdotal evidence from the deciduous fruit industry says that farmers have noticed a steady increase of 2°C to 3°C in the Western Cape over the past three decades. This may have imprinted itself on the alcohol levels recorded on wine labels since the 1970s. By 2050 the coastal areas of the Western Cape will see an additional 0.5°C to 1°C increase. Inland, where those coveted sea breezes may not touch with their moderating cool, the increase could be greater. And the more they climb, so the sugar content in grapes will keep apace. Could the Cape's wine labels start boasting the obscurely high alcohol levels of Turley Wine Cellars? Looks like we'll be drinking dry 'table' wines that have moved convincingly into the alcohol level of fortified wine even though they haven't had even the smallest dash of spirit added. Leonie Joubert is a freelance science journalist with a special interest in climate related issues. Also see a recent article by the Distell News Service on the same topic: When is a table wine not a table wine?