Keith Stewart enforces a strict no-hoarding policy when selling his garlic at New York’s Union Square Greenmarket.

“We always run out,” he says of his pungent product, a large-cloved variety known as rocambole. A neighbor brought back some from Italy 40 years ago, and for almost two decades, Stewart started has grown it organically in New York’s Hudson Valley.

Like the chefs who hound Stewart for his harvest, Americans have developed an enormous appetite for garlic.

And that demand has spurred an industry offshoot – gourmet garlic such as Stewart’s, special varieties that connoisseurs claim are to typical supermarket cloves as a great Gruyere is to processed cheese slices.

“It’s a different product,” says Peter Hoffman, a chef who uses Stewart’s garlic at his Savoy restaurant in New York. “The sweetness of flavor, the creaminess of texture, not to mention the ease of use in terms of peeling.”

Though most garlic sold in mainstream grocers is the common so-called softneck variety – most of which comes from China and California – more consumers are seeking out the more distinct flavor of hardneck garlics.

“With the supermarket stuff, you don’t know how old it is, and it has a harshness you don’t find in rocambole,” says Kemp Minifie, executive food editor at Gourmet magazine. Hardnecks are “juicier, the flavor is better.”

Just as consumer appreciation has allowed the artisanal cheese business to flourish, garlic is now having its day.

“When I used to sell garlic, it was just garlic,” says Gene Frey, a coordinator at Fedco Seeds Cooperative in Waterville, Maine. “Now people want to know the specific characteristics” of each variety.

During the last 20 years, per capita consumption of garlic has gone from less than a pound to 2 1/2 pounds, according to the U.S. Department of Agriculture, which attributes the growth in part to the rising popularity of ethnic foods.

And between 1995 and 2005, garlic production in the U.S. grew 20 percent to about 537 million pounds. During the same period, imports of fresh garlic went from 62 million pounds to 126 million, the USDA says.

Sporting fewer, but larger, cloves than softneck garlics, hardneck varieties (the name refers to their stiff stems, something that has been bred out of softnecks) are grown throughout the country.

But to find it, you’ll probably have to look at farmers markets or shop online.

If you are in need of a garlic fix, try this heady garlic-potato soup, shown above. Topped with garlic chips and chives, the garlic rich soup also makes use of chopped leek and heavy cream.

Bob Anderson, a retired management consultant from Bangs, Texas, started his GourmetGarlicGardens.com Web site in 1997 to sell hardneck garlic for as much as $16 to $24 a pound.

During those first years, he sold a couple hundred pounds a year. Today he sells about a ton, and says people are drawn to the “beautiful, rich garlicness and rich warmness and pungency” of the hardneck varieties.

Though he grows some of his own, most of the garlic Anderson sells comes from a few dozen small farmers around the country, many of whom are in remote areas with no local market for their crop.

Fewer varieties than believed

A common myth about hardnecks is that there are hundreds of varieties. This is because genetically identical cloves will produce dramatically different flavors and textures depending on the climate, soil and other variables of where they are grown.

But new research has revealed that in the U.S. only 10 genetically distinct hardnecks and two softnecks are grown.

“There was a great deal of confusion about what was what,” says David Stern, executive director of the Garlic Seed Foundation, a Rose, N.Y., group that serves as a resource for small farmers.

Not everyone has been pleased by the clarification, says Stern. Many farmer have been “making money selling ‘400 varieties’ of garlic,” he says. “I’m the schmuck that has to tell them, ‘Sir, there’s only 10.”‘

Among those 10 (which include Stewart’s rocambole, as well as purple stripe and silverskin), porcelain is one of the more popular varieties. Known for its thick, parchment-like wrappers and large, plump cloves, it is sold under various names, including Georgia Crystal, Georgia Fire and Romanian Red.

Nuances subtle

Few dispute that hardnecks offer better flavor than common garlic. But whether the nuances between hardneck varieties are meaningful is a matter of debate, even with garlic’s impressive terroir properties (the ability of location to influence taste).

“I would probably flunk a blind taste-ID test, as would most people,” says Naomi Scanlon, who along with her sister runs Two Sisters Garlic, a Canterbury, N.H., company that grows and sells seven to eight varieties of hardneck a season.

Which isn’t to say there aren’t differences.

“It is not the taste so much that is distinctive, but how they cook up, their texture and taste retention,” Scanlon says. “Some burst with flavor immediately upon a bite while others sneak up on the mouth either with their true flavor and/or heat.”

Of course, gourmet or otherwise, some aspects of garlic remain the same. And fans such as Anderson make no apologies.

“The age of designer garlic breath has arrived,” he says.