The American whiskeys tend to fall roughly into two categories. Some, like Balcones, Leviathan and St. George, a well-regarded single malt from Alameda, Calif., use Scotch as a model, with some even importing peat-smoked malt directly from Scotland.

Steve McCarthy, who makes the heavily peated McCarthy’s Single Malt, alongside a range of eaux-de-vie, at the Clear Creek Distillery in Portland, Ore., said he was inspired to create a Scotch-style whiskey after tasting a 16-year-old Lagavulin on a trip around Ireland in 1992. “I thought, ‘I would like to go home and make that,’ ” he said.

Some 15 years after Mr. McCarthy’s first release, even many hard-core Scotch drinkers say he succeeded.

“I was skeptical at first,” said Nathan Keeney, a computer programmer and Scotch devotee from San Jose, Calif. “But if I were in a blind tasting, I wouldn’t have been able to tell you it didn’t come from Islay,” the Scottish island home of world-famous peat monsters like Ardbeg and Laphroaig.

Unlike those Scottish distillers, however, American whiskey makers face few limits on what they can call “single malt” — a freedom that many have grabbed with both hands. Theirs is the second category of American single malts: a catchall grouping where the sole defining characteristic is aggressive innovation.

Wasmund’s, a whiskey from Sperryville, Va., gets some of its signature fruit notes from a bag of apple wood chips that steeps in the barrel along with the aging whiskey, a process that might cause a Highlands distiller to jump out of his kilt.

To create its Pine Barrens Single Malt, Long Island Spirits, in Baiting Hollow, N.Y., starts by distilling a commercial beer — Old Howling Bastard, a barley wine from the nearby Blue Point Brewing Company — and then aging it in oak barrels.

The result is hoppy and bready, with strong citrus notes, a world away from the mellow smokiness of a typical Scotch. And that, said Richard Stabile, the owner of Long Island Spirits, is the point. “It’s part of the pioneer spirit to try to do something by putting your own signature on it,” he said. “I’m not trying to make someone else’s product.”

So American single malt isn't ACTUALLY single malt?!

I. Am. Disappoint.