Charleston has lots of knowledgeable eaters, which is another way of saying it's home to plenty of eaters with strong opinions. And while those opinions frequently diverge, Charlestonians have reached a rare unanimity on Stiegl Grapefruit Radler, which has become a local sensation in the span of a few weeks.

"The distributor knew it would be a big hit, but they didn't know it would be this popular," says Mark Sahara of Charleston Beer Exchange. "It's flying off the shelves."

The radler concept is far from new: According to legend, the Bavarian drink originated when a tavern keeper in the 1920s had the bright idea to build a bike path from Munich to his establishment. Franz Kugler wasn't equipped to serve the thousands of cyclists who followed the forest trail on a Saturday afternoon, so he stretched his beer supply with lemon soda and named the result for his customers. ("Radler" means cyclist in German.) The drink -- kin to a British shandy -- was immediately hailed for its refreshing, thirst-quenching properties, which may help explain its warm reception in Charleston.

A few months ago, Charleston had its first shot at Stiegl's brew, an Austrian radler uniquely made with grapefruit soda. ("The epitome of the style in this beer drinker's opinion," the St. Louis Post-Dispatch's beer writer Ian Froeb last month declared in a column praising the drink's "clean, pleasantly tart grapefruit flavor.") Brooks Reitz was an early proponent of the beverage, putting it on the menu at Leon's Oyster Shop, which opened in the last week of May.

"I tried it for the first time at Leon's," a staffer at Bakehouse Charleston said when reached by phone yesterday afternoon. "We've sold a ton of it today."

Because Stiegl Radler clocks in at 2.5 percent ABV, it's ideal for daytime drinking. Justin Coleman, manager of The Ordinary, where the Stiegl Radler figures into a summery Ting Collins, says he noticed an enormous uptick in radler interest following the July Fourth holiday; it's possible Leon's patrons sought out the drink for their barbecues and other casual holiday gatherings.

(Not everyone who's looked for Stiegl Radler has been able to find it: Charleston Beer Exchange, which usually carries one case each of its esoteric beers, has tripled its Stiegl Radler order.)

But the low-alcohol level also means drinkers are paying a high price for not much booze. A four-pack of Stiegl Radler sells for $10.59.

"They're willing to pay a premium for something crushable," Sahara says.

More domestic breweries are now experimenting with radlers, but the list of U.S. radler makers doesn't include any Charleston producers. According to Sahara, the closest local approximation is mixed on the fly.

"At Holy City, they'll mix pilsner with lemonade from the fridge," he says.

Of course, if the current radler craze keeps up, local contributions to the category may become more formalized.

"It's doing beyond expectations," says Sahara, who describes the Stiegl Radler as the perfect brunch beer.