The oversized bottle, billed as a very old and rare Burgundy, was uncorked at a grand dinner in Chicago hosted by a Midwestern oenophile. It should have been a wine to savor unreservedly. But one couple in attendance—the wine writers Mary Ewing-Mulligan and Ed McCarthy—were troubled by the double magnum (equal to four regular bottles) of Domaine de la Romanée-Conti Romanée Conti 1945.

In McCarthy’s opinion, “it tasted very good, but we felt it was surprisingly youthful for a wine that old. We also knew that the production in 1945 was extremely small. Most of it had already been consumed. Red flags were raised by a rarity in such a large format.” Later the couple queried Aubert de Villaine, owner of the domaine, about the big bottle. “No double magnums of Romanée-Conti were made in 1945,” de Villaine replied.

The Midwestern collector had been the victim of fraud, a plague that appears to be worsening as trophy-wine prices rise steeply in lockstep with those of trophy art. Indeed, some wines created to be mere drinks have come to be valued like masterpiece paintings.

In 2006, Wine Spectator magazine’s auction index rose by 45 percent. This April, a single imperial (six regular bottles) of Château Latour 1961, a classic Bordeaux, was knocked down at Christie’s in Los Angeles for $59,250, a 91 percent rise. Then in May a case of Romanée-Conti 1985 sold at Christie’s in New York for $237,000 (including buyer’s premium), a leap of 125 percent from its previous sale price and the most ever paid at auction for a case of Burgundy. Also in May, at Sotheby’s New York, three cases of Château Pétrus 1982, the rare Pomerol, fetched $71,700 each, a 50 percent increase.

It’s no wonder, given the potential returns, that skilled counterfeiters have redirected their talents from Rolexes to Romanée-Contis, from Piagets to Pétrus. Many in the fine-wine world downplay the problem of fraud. Not Serena Sutcliffe, London-based international director of Sotheby’s wine department. “The problem is much worse than people think,” she says. “But only at the top level. That’s where the big money is to be made.”

Nobody can say for sure how many counterfeit bottles penetrate the market, simply because the best fakes are never discovered. That’s especially true now, with an expanding clientele of deep-pocketed neophytes from India to the Ukraine, who have little idea what the real thing tastes like, throwing money at prize vintages. In 2006 worldwide wine auction sales reached a record $241 million. If 5 percent of the lots sold were fakes, as many experts suggest, the scam would amount to many millions of dollars, and that’s not counting fakes sold through private dealers and shops.

Sutcliffe believes the fakers are mainly based in Europe, where the packaging expertise and equipment are concentrated. “Whenever we uncover fakes,” she says, “they always seem to be traceable back to the same sources. And yet nothing ever seems to get done about it.”

Wine fraud isn’t likely to reach the shelves of your local liquor shop. It’s a con game confined primarily to auction houses and high-end wine dealers, and to their deep-pocketed clientele. “We regularly reject wines from would-be consignors,” says John Kapon, president of New York–based auctioneer and retailer Acker Merrall & Condit. “But fraud is not an A-to-Z problem across all wines. It’s only an A+++ problem.”

Among those A+++ wines are Bordeaux from châteaus Pétrus, Cheval Blanc, and Lafleur, including the classic vintages 1947, 1961, and 1982. Although auction prices oscillate, the youngest of these have typically sold this year for more than $2,000 a bottle and the oldest and rarest sometimes for more than $10,000 each. The Burgundies that are natural faker fodder include the ultrapricey Romanée-Contis. Kapon was suspicious of a recently consigned bottle of the domaine’s La Tâche 1971—a particularly successful vintage currently selling for about $3,000 a bottle—so he cut the metal neck capsule to examine the stopper. “The vintage stamped on the cork was 1970,” he says. “That wine is worth only a quarter of what the 1971 sells for.” A false label showing the more valuable date had apparently been pasted on a bottle from the previous year. Most consignors, according to Kapon, are victims themselves, having unwittingly bought the fake wine.