T his holiday season, while perusing the shelves of your favorite beer shop, you may come across a bottle that looks like it belongs more with the sparkling wines than with ales and lagers. But look past the caged and foil-covered cork, down below the gold-embossed art nouveau label bearing the name Infinium, and you’ll see evidence that it is indeed an ale.

And a most unusual ale, at that. The product of years of collaboration between the Boston Beer Company (makers of Samuel Adams beers) and the centuries-old Weihenstephan Brewery of Germany, Infinium represents nothing less than a revolution of brewing under the Reinheitsgebot—the Bavarian purity law that limits ingredients to water, malted grain, hops and yeast.

Inspired by Weihenstephan brewers’ desire to collaborate with Boston Beer on a project, BBC founder Jim Koch says he envisioned a “white space” within the limits of the Reinheitsgebot. To fill that space, he says, they had to rethink both the brewing and malting process, so they could create a strong, all-malt beer that was not overly sweet, cloying or heavy.

“I imagined a beverage somewhere between a Champagne, a dessert wine and the Samuel Adams Noble Pils,” says Koch.

Packaged in a bottle reminiscent of a German Sekt, Infinium pours a light gold color. Its perfumed aroma offers generous spicy notes against a backdrop of honey and florals, while the full and off-dry body carries gentle notes of peach and pear alongside biscuity malt and clove and ginger spiciness, leading to a finish that’s warming without being hot.

Koch says that he sees Infinium as the Opus One of beer. “[It’s] a coming of age moment when the Old World recognized the achievements of the New,” he says. While history will no doubt be the judge of that, what Boston Beer and Weihenstephan have definitely created is a unique and flavorful bottling well suited for the approaching season of celebration.

Rumor has it that two more collaborative beers from this intercontinental brewing dream team will be hitting the shelves in 2011. We’ll just have to wait and see what they come up with next.