Conjured up by Boston Beer Co. founder Jim Koch, Sam Adams Utopias costs $140 per decorative flask, and a recent vintage is 25.6 percent alcohol by ­volume. It is, according to Guinness World ­Records, the strongest commercially available beer in the world.

Some perspective: Most mass-produced beers in the U.S. hover around 5 percent. So why would Koch make such a strong beer? “Think Star Trek,” Koch says. “Think of taking beer—and brewing ­science—where it has never been before.”

Koch and a handful of other mad hatters in America’s quarter-century-old craft-beer movement have for a while now been taking part in an engaging sideshow: the race to make the strongest beer the world has ever seen. Koch is leading, but Sam Calagione, founder of Dogfish Head Craft Brewery, in Milton, Delaware, is on his tail. A vintage of Dogfish Head World Wide Stout reached more than 23 percent, allowing Calagione to claim he’s made the world’s strongest dark beer.

Strength brings bragging rights but isn’t precisely the goal. At a.b.v. levels above 10 percent, beer begins to take on complex, ­unbeerlike characteristics. Nose a brandy snifter of Utopias and you’ll swear it’s cognac. Indeed, these ultrastrong (and expensive) beers aren’t targeted at college kids looking to get drunk but are pitched instead to the wine-and-spirits crowd.

Until Koch ­began the race for the ­superbeer, 12 percent was about as strong as beer got; beer yeast became spent at that level, stopping fermentation. But by culturing strains of superyeast and running beer through multiple fermentations, ­brewers have broken that ­barrier.