With his plaid shirt, cowboy hat and neatly trimmed mustache, Jess Graber is as quintessentially Western as sagebrush and the Marlboro Man. So when Graber decided to enter the whiskey business several years ago, he realized that making an eastern whiskey such as bourbon or rye just didn't feel right.

 "It doesn't make sense to me to make Kentucky whiskey in Colorado," says Graber, manager of Stranahan's Colorado Whiskey, which has been produced in Denver since 2004 using barley grown in the northern Rockies. "We thought we should be making something that's indigenous. That's generally what whiskey is - it's a regional spirit, it tastes like where it's made."

These whiskeys are essential elements in the nation's drinking culture. Until recently, many American whiskey drinkers would have considered the production of a different kind of whiskey - such as that proposed by Graber - to be an act of such unpatriotic inelegance that it would be tantamount to serving Chardonnay and Brie at a bull-riding competition.

The modern story of American whiskey is largely one of nuance. Today's market is dominated by bourbon and Tennessee whiskeys and, to a smaller extent, rye whiskey - spirits that have production and aging requirements clearly defined by federal law, and that differ from one another largely in the proportions of corn, rye and other grains in their recipes, or mashbills.

In recent years, however, more distillers have begun stepping outside the whiskey mainstream, experimenting with different grains and production techniques and creating unique styles that are a product of curiosity and ingenuity, rather than centuries of tradition. In the process, these distillers are making some of the more intriguing spirits on the market, and are breathing new life into American whiskey.

"There is now a conversation to be had about the categories beyond bourbon (and) rye, and it's a conversation that didn't really exist a few years ago," says Larry Kass, director of corporate communications at Heaven Hill Distilleries in Bardstown, Ky. "We've really succeeded in getting a new generation of straight whiskey drinkers. ... They're now saying, 'Is there anything else out there?' "

Heaven Hill produces bourbons and ryes such as Evan Williams and Rittenhouse, but in 2005 it ventured beyond these categories with an esoteric spirit called Bernheim wheat whiskey. As its name suggests, Bernheim is made with a mashbill composed primarily of wheat, which gives the whiskey a softer, more floral aspect.

While Bernheim is a variation on the familiar bourbon theme, other distillers are making styles that reach deeper into whiskey's early history, or that abandon tradition altogether. Fritz Maytag at Anchor Distilling on Potrero Hill is credited with helping to spark this innovative boom in 1996, when he began producing whiskeys made entirely from rye grain, employing minimal aging to create a spirit like those found in early America; today Anchor distributes three styles of Old Potrero whiskeys.

Around the same time, Steve McCarthy at Clear Creek Distillery in Portland, Ore., began selling McCarthy's Oregon single-malt whiskey - a spirit made from peat-malted barley imported from Scotland that is then fermented and distilled in Oregon - that bears more relation to the smoky Scotches from Islay than to other American whiskeys.

At St. George Spirits in Alameda, Jorg Rupf and Lance Winters make whiskey using the same approach they take with the unaged fruit brandies known as eau-de-vie. "The style of the eau-de-vie maker is the Chez Panisse philosophy - it's the least manipulative, where you count on using the best-quality raw material, and then shepherd that through the process and make sure that all the things you loved about that raw material show up at the party," Winters says.

When making St. George whiskey, this translates into sourcing barley from the Midwest (about 15 percent of the whiskey's barley is purchased in Europe and smoked over alder and beech in Bamberg, Germany), then tweaking the roasting, fermenting, distillation and aging processes to ensure the barley's flavor comes through.

Each distiller uses different tools to create its own unique spirit. St. George Spirits ages its whiskey in used bourbon barrels - which impart less oak flavor to the spirit - but also utilizes used Port casks, which accent the whiskey's cocoa notes. At Tuthilltown Spirits in Gardiner, N.Y., co-owner Ralph Erenzo ages his Hudson single-malt whiskey, made from Canadian malted barley, in new, charred-oak barrels. These barrels are similar in style to those used for bourbon or rye, but are much smaller, some holding as little as 3 gallons. The whiskey is aged in these small barrels for less than a year, which Erenzo says gives the whiskey a mature character without allowing the flavor of oak to dominate.

Among the techniques Stranahan's employs is preparing its wash - the yeasty, low-alcohol liquid that results from the initial fermentation - using craft-brewing techniques at Oskar Blues brewery in Longmont, Colo. It's an apt technique, considering that whiskey is often described as simply distilled beer, and one that Graber says purifies the wash and results in a more refined spirit.

At Charbay Winery & Distillery in St. Helena, distiller Marko Karakasevic takes the whiskey-as-distilled-beer concept literally. In 1999, Karakasevic distilled around 1,000 gallons of whiskey from 20,000 gallons of pilsner beer - including not only the barley, but the hops as well. After an initial release in 2002, a second bottling of Charbay whiskey was released last summer. Karakasevic says the hops add top-note aromas and flavors of fruit, spice and fresh herbs to the whiskey. Three and a half weeks of painstaking distillation were required to preserve the hops' delicate flavors; Karakasevic notes, "People say it tastes like beer, and I say, 'Jesus, I hope so.' "

These innovative whiskeys can be some of the most fascinating spirits behind the bar, says Daniel Hyatt, bar manager at the Alembic on Haight Street in San Francisco. "There's a certain excitement about them that's not in the way you'd get excited about a new bottling of a single-malt Scotch," Hyatt says. "There's something about ordering a bottle of (whiskey) you've never heard of, and having no idea what you're about to get."

This element of mystery works both ways; for consumers accustomed to the taste of Maker's Mark and Jack Daniels, a new style of whiskey can be an uncertain thing. "People are always clamoring for something new, but they're also clamoring for something that they can pigeonhole into a category that they already know," Winters says.

Despite these challenges, Winters believes the arena of untraditional American whiskeys is ready to grow. "There are some amazing things coming around from a number of distillers, and it's going to require people to step into an area they've never been before. They'll be really glad they did."

Buying guide
Several styles of American single-malts and other innovative whiskeys are available at well-stocked liquor stores and bars. Here are a few notable releases worth seeking out.

Bernheim Original Kentucky Straight Wheat Whiskey ($44) This wheat whiskey has a light, fruity aroma that is distinctly bourbon-like, but the flavor is softer and sweeter, with a lingering, deeply honeyed finish.

Charbay Hop-Flavored Whiskey Release II ($325) A paradigm-shifting whiskey. The aroma is elaborately floral, with graceful notes of chamomile and pears; when tasted, the whiskey identifies itself as a clean, pure concentration of beer, with a lingering hoppy finish of bananas and fresh bread.

Hudson Single-Malt Whiskey ($45) Aged in new, charred-oak barrels, this New York whiskey has a rich caramel aroma and a robust, woody flavor of brown sugar and dried peaches.

St. George Single-Malt Whiskey ($50) St. George distillers Lance Winters and Jorg Rupf make their whiskey in the eau-de-vie tradition; this is evinced by the spirit's delicately sweet aroma and its muted inflections of cocoa and nuts, which reflect the gentle flavors of the barley and the complex aging process.

Stranahan's Colorado Whiskey ($57) This Colorado single malt has an austere, vegetal aroma, and the flavor is crisp and grassy, with a subtle, nuanced brown-sugar sweetness tinged with citrus peel and chocolate.