BORDEAUX - Producers of Sauternes, France's world-famous sweet wine, are up in arms about a proposed high-speed train line they fear could sour their tipple.
The wines, a staple with foie gras at French Christmas and holiday dinners and long a favourite of the British royal family, owe their sweetness to a morning mist generated by the cool waters of the local River Ciron -- around 13 degrees C (55 degrees F).
The mist flows over the warmer plains of the Sauternes growing region, which lies below Bordeaux in southwest France, and encourages a special type of mould known as "noble rot" or botrytis cinerea that attacks the grapes before they are fermented.
The result at harvest time is grapes that are violet and shrivelled rather than golden and ripe. The noble rot also bolsters sugar levels and imparts the complex notes of fruit, honey and nuts that make Sauternes the benchmark for dessert wines around the world.
And while the proposed high-speed line will not run directly through the wine-growing region, it will run through the Ciron valley, sparking fears it could affect the fragile micro-climate on which the wine depends.
Philippe Dejean, head of the union of sweet wine growers of Bordeaux, said he was "very worried" about the proposed Bordeaux to Dax TGV -- the French acronym for high-speed train -- that is planned to become operational in 2027.
"We are calling on all those who love sweet wines to make their feelings known," he said.
Xavier Planty, head of the local Chateau Guiraud producer, warned: "If the waters of the Ciron are warmed up, the mist will not form as easily. We can't take the risk that everything will be messed up."
Activists are calling for an inquiry into the proposed line and have threatened to take their case to the European Court of Justice.
At the moment, "there is nothing at all" about the impact of the proposed rail line on the wine growing area, complained Bernard Farges, head of an association of Bordeaux wine growers.
The RFF (French Rail Network), which is running the project, said that it had "of course done impact studies" but this does not seem to have satisfied the activists.
Local MP Gilles Savary said there was a wide spectrum of opposition to the project, including "local elected officials, environmental activists, foresters, hunters and wine growers."
'Superior first growth'
The entire Sauternes appellation has only 5,000 acres (2,000 hectares) of vines, a tiny fraction of the 285,000 in the wider Bordeaux region.
Well-known Sauternes include Chateau Rieussec and Suduiraut. But the most highly rated is Chateau d'Yquem, classified as a "superior first growth" and considered one of the world's great wines, at times with a pricetag to match. While a good bottle can be found for 25 to 30 euros (S$40 to S$49), the better ones can run up to 300 euros and more.
In 2011, a 200-year-old bottle of Chateau d'Yquem set a new world record for the most expensive bottle of white wine when it was sold in Britain for 75,000 pounds (S$153,769).
Due to the mould, Sauternes wines have high levels of residual sugar, which, combined with the grapes' natural acidity, act as preservative agents which allow them to age for centuries without becoming undrinkable.
The British royal family is known to be partial to a drop of Sauternes and Queen Elizabeth II was rewarded for a gruelling day of ceremonies at the 70th anniversary of D-Day with foie gras served with a Sauternes jelly.
The wine also goes well with zesty foods whose flavours are not overpowered by the sweetness of the wine -- strong cheese like Roquefort or Stilton, roast pork with mango and ginger, or fish in a rich cream sauce.