Blended Scotch is created by mixing great whiskies. To some connoisseurs, that makes it suspect. To everyone else, that makes it delicious. A recent boom in blends has revived the controversy.

You'd better be fluent in metaphors if you're going to talk with the people who make or market blended Scotch. Over the past few months, as a succession of representatives from Dewar's, Cutty Sark, Chivas Brothers and other fine Scottish exports paraded through my office in kilts and tartan neckties, I heard about orchestra conductors, bricks and mortar, sports teams, best friends and crowded rooms. In case the meaning of all this isn't instantly clear, I'll try to interpret.

Blended Scotch is a mixture of two kinds of whisky, grain and malt. Grain whisky is distilled mainly from corn, and has a light, sugary, pleasant flavor. Malt whiskey is distilled from barley; it's made in as many different styles as there are rocks in Scotland, but generally malts have a stronger and more assertive character than grain whiskies. (The famous single malts that we hear so much about are just individual malt whiskies.) To the metaphor mongers, the malts are the bricks that provide the structure of a blended Scotch; the mortar is the grain whisky that, because its flavor is comparatively neutral, binds the malts together. (Or, as I was also told, the malts are the paint and the grain whisky is the canvas.) The orchestra conductor is the master blender, whose job is to get as many as 40 different whiskies to play together harmoniously. The specific whiskies in a blend may be varied from batch to batch, depending on availability; they are rotated in and out like athletes, but the team plays just as well no matter who's on the field.

The best-friend analogy was perhaps the most enlightening, because it told me a lot about the fears of the people who used it. People have strong feelings of affection for their favorite single malt, just as you do about your best friend. But as wonderful as your best friend may be, he's not perfect, is he? And isn't it a little tiresome spending all your time with one person? Don't you occasionally enjoy a large, lively party? Your best friend might even attend the party—just as some of the best single malts turn up in some of the great blended Scotches—but there will be all sorts of friendly new faces in the room too.

What the people who used this analogy were really getting at is that many drinkers, Americans mostly, have been spending a little too much time with their best friend. Consumption of single malt Scotch in the United States has soared, while sales of blends have fallen to half what they were two decades ago. This has the men in kilts deeply troubled and is the reason they've resorted to rhetorical gymnastics. (It is also the reason that the Cutty Sark booth at WhiskyFest, a distillers' expo held in New York last November, was staffed not by men in kilts but by a squadron of Penthouse Pets in black dresses that seemed about three sizes too small.) When I told a rep for one single malt that I wanted to write about blended Scotch, he said, "Oh, good. Those guys really need some help."

That may be, but they must suspect that their luck is about to turn. With much fanfare, Dewar's has launched a 12-year-old blend, its first new release in four decades. It's good, too—richer and more resonant than the brand's trademark 8-year-old White Label. Early next year, Cutty Sark will answer with a blend of its own, although for now the company is guarding the details like nuclear secrets. Johnnie Walker makes a Blue Label in tiny quantities that are in inverse proportion to the staggering $210 price tag. The president of the Scotch Malt Whisky Society has placed a very old, very tasty blend called the Classic Cask on the market. And Springbank, makers of single malts that cause connoisseurs to speak in tongues, has begun exporting its extraordinary blend, Campbeltown Loch, to the United States. All these new Scotches are aimed straight at the single-malt drinker; they are intense, complex spirits that reward slow, careful sipping.

The strange thing about the blenders' desire to woo single-malt fans is that when blended Scotch was invented, more than a century ago, it was a response to the unreliability of malt whisky. Distilleries in those days did not have computerized quality-control departments; if the year's grain crop was off, or the still was acting up, a normally great whisky would turn out bad. So a distiller would mix it with other whiskies—some of his own, along with surplus bought from other makers. This way he could hide his whisky's flaws; by adjusting the recipe slightly, he could turn out a good blend even in bad years. The Scots were so skilled at this sleight-of-hand—arguably a trickier and more demanding procedure than distilling—that their blends were acclaimed around the world long before anyone thought to export the single malts. In fact, blends still outsell single malts by a wide (though narrowing) margin.

This background was lost on the Americans who took up single malts in the 1980s and '90s. In their view, the idiosyncrasies, even the imperfections, of single malts make them more interesting—and thus, better—than blends. Blended Scotch, because it is polished and corrected, is seen as compromised. Some whisky freaks go so far as to suggest that blended Scotch is a waste of perfectly good single malts, a waste mitigated only by the fact that many single malt distilleries would go out of business if the blenders didn't buy most of their output. The devotees of Macallan, Ardbeg and the rest regard blends the way folkies regarded Dylan's electrified set at Newport in 1965: as a debasement of something beautiful and pure.

The trouble with purity, as Calvin Trillin pointed out, is purists. In this case, the purists have it all wrong. In Scotland, nobody sees blended Scotch as the bastard brother of single malts. It's not inferior, not superior, just different. The Scots would not dream of giving up their Chivas, their Grant's, their White Horse.

There are even those who claim that blended Scotch is a more interesting object for connoisseurship than single malts. The writer and whisky consultant Jim Murray, for one, argues that the very smoothness of blends presents the connoisseur with the enjoyable challenge of picking out the malts it contains. Blends may have begun as a way of covering up inferior whiskies, but today great blends are made with great malts. Cutty has substantial amounts of Glenrothes and Glengoyne, with some Tamdhu and Highland Park thrown in to keep things lively. The core of Chivas is the Speyside malt Strathisla. And Campbeltown Loch is built from the coveted malts of the Springbank distillery, some of which have been aged between 25 and 30 years.

Tasting those malts, though, seems to require the kind of sensitivity described by Brian Eno in his song about an elite espionage specialist: "Her sense of taste is such that she'll distinguish with her tongue/The subtleties a spectrograph would miss." For those of us with slightly less acute palates, it may be enough to know that Johnnie Walker, like the Islay malts at its heart, is dense and smoky, while Chivas has the more subtle character typical of Speyside whiskies. And even that may be complicating the issue.

After I'd wandered WhiskyFest for a couple of hours, I met a man named John Glaser who helped put things in perspective. Glaser had recently started a company called Compass Box, and he was there to introduce its first product, Hedonism, a blend of two grain whiskies with no malts at all. (This is why the label reads "Whisky from Scotland" rather than "Scotch.") I asked him where it was made.

"In my kitchen," Glaser said.

Then I asked how long he'd "married" the whiskies—that is, let them sit in the same vat for a few months after blending so they could get used to one another.

"About a day," he said. "Where did you hear that word?"

I had picked it up about 20 minutes earlier, from one of the men in kilts.

"It's meaningless! All these big companies like to use these big words, because it makes it sound like they're doing something special. I used to work for one of them, and I talked the same way these guys do. Have you heard about the orchestra conductor?" I told him I had.

"Paint and canvas? Bricks and mortar? Listen," Glaser said. "These guys throw all these words around, but all they're trying to do is make something really delicious."

I let that sink in while he poured me some whisky.

Hedonism is an oddity. To use the paint-and-canvas analogy one last time, Hedonism is all canvas; the brush strokes of sea brine and wood smoke you expect in a Scotch are missing. If whiskies are judged on complexity, Hedonism is a loser. So why do I like it? Because it tastes good.

With one sip, the ideas I had built about blended Scotch fell apart. A blend isn't a symphony or a brick house or a sports team. It's not a puzzle either, some kind of how-many-single-malts-can-you-find-in-this-picture quiz. It's just a great thing to drink.

The men in kilts know it. Now they just have to learn how to say it.