A recent two-day wine auction held by New York City’s Acker Merrall & Condit featured an unusually rich selection of mature Champagnes, including such treasures as the 1961 Dom Pérignon and the 1966 Louis Roederer Cristal. As he hammered down the first lots of vintage bubblies, Acker president John Kapon advised the Champagne aficionados in attendance to reach into their wallets now or face the prospect of having to dig even deeper 12 months down the road.

“I guarantee you all these prices will be significantly higher this time next year,” Kapon said between bids. Sure enough, six bottles of the ’61 Dom promptly sold for $8,000 and eight bottles of the ’66 Cristal fetched $22,000. The market for older Champagnes has lately sprung to life, thanks to the growing interest of an unlikely set of buyers: young American collectors.

It used to be that old Champagnes (generally defined as wines with at least 30 years of age on them) were the domain of crusty old Britons, who preferred their bubblies less effervescent and a little more winey, who savored the telltale aromas of mature Champagnes (mushrooms, coffee, honey, hazelnuts), and who tended to cellar the wines in substantial quantities. Americans, by contrast, liked their Champagnes fresh and sprightly. That is still mainly the case, but in recent years, some young, affluent U.S. oenophiles have become aggressive buyers of ancient Krugs and Dom Pérignons.

Robert Rosania, a 37-year-old principal with New York real estate firm Stellar Management, is one such collector. He grew up in a family that prized good food and wine, but he didn’t discover the pleasures of old Champagne until four years ago. He has been making up for lost time ever since. He is now, according to Kapon, the most aggressive buyer on either side of the Atlantic and has quickly accumulated what is apparently an unrivaled collection of Champagne rarities.