Peer into any world-class wine cave and you’ll likely find several dusty, amber-colored bottles of Château d’Yquem, the famous sweet Bordeaux produced at an estate that dates at least to the 16th century. "It’s represented in all the best collections," says Jamie Ritchie, head of North American wine sales for Sotheby’s. Hence it’s represented as well in every high-end wine auction; several dozen lots from various vintages are usually available, to the exclusion of almost any other sweet wine.

Yquem is the glorious exception to every rule; it literally constitutes a category of its own. In the famous Classification of 1855 — a ranking, still used today, of all the French châteaus — it was awarded a special designation atop all other wines from Sauternes, Bordeaux’s sweet-wine zone. Few wines have such an illustrious history: Thomas Jefferson visited the château and made a big order, also pressing some bottles on his pal George Washington, who became a devoted fan.

Yquem isn’t made every year: It’s produced only when a fungus called Botrytis cinerea, affectionately known as "noble rot," attacks the grapes in just the right way, exponentially concentrating their sugar. The resulting wine — honeyed, perfumed and rich — has so much sweetness and acidity that it can improve for decades, or centuries. "One of the great things is that you can absolutely drink a young vintage of Yquem now, or it can significantly outlast the drinker himself," says Paul Hart, of Chicago’s Hart Davis Hart Wine Co. Word is that the famed Yquem of 1811, known as "the year of the comet" for the particularly long appearance put in by one such celestial visitor, is still going down smoothly.

Vintages That Matter

Amazingly, 19th-century vintages of Yquem still come up at auction: A single bottle of the 1811 brought $42,500 at Christie’s London in 2006, and the equally historic 1865 and 1893 would command similar sums. The all-time record for a bottle of Yquem was fetched by the 1847: $71,675. The 1920s produced three collectible years — 1921, 1928 and 1929 — generally selling for $3,000 to $7,000 a bottle. The 1967 (shown above with the 1959) and the 1975 are among the most traded. Well positioned between great drinking now and long-term cellaring potential, they can be had, respectively, for around $500 and $1,000 a bottle. Among more recent years, the trio of 1988, 1989 and 1990 come up for auction frequently, with prices ranging from $250 to $500. The 2001 is a modern classic — a bottle can be yours for around $600.

The Château Today

Produced from Sémillon and Sauvignon Blanc grapes, Yquem isn’t released until several years after the vintage is made. The 2005, another heralded year, is the current release, priced around $500 a bottle. Although the château was owned for centuries by the Lur-Saluces family, LVMH bought a majority stake in 1999, adding it to other French wine jewels like Champagne Krug and Veuve Clicquot.

A Matter of Taste

Many auction experts consider Yquem undervalued, partly because demand from Asia has pushed the market in other directions. "Asian collectors have not warmed to sweet wines as they have to red Bordeaux," says Robert Sleigh, of Sotheby’s. He estimates that Asian buyers account for nearly 60 percent of the major wine sales by value, leaving opportunities for Yquem fans in the U.S. and Europe.

What to Look For

As it ages, Yquem goes from a golden orange color to a dark amber. As with any wine, the ullage — the space between the cork and the capsule — increases over time. Some half bottles are produced, but the standard 750 milliliter is the size most often traded at auction. Unusually, collectors pay no premium for oversized bottles of Yquem. "A little goes a long way," says Paul Hart. "You only consume a small amount." Wines in their original wooden cases — OWC in catalogue parlance — often have added value.

"Château d’Yquem" originally appeared in the November 2009 issue of Art+Auction. For a complete list of articles from this issue available on ARTINFO, see Art+Auction's November 2009 Table of Contents.