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Behold Brooklyn’s liquid gold!

It costs more than three ounces of silver, a barrel of oil or a cup of the finest caviar — but not a single Brooklynite has tasted what’s likely the borough’s most expensive drink.

No customer has ever ordered a glass of Char No. 4’s $100 per ounce bourbon, a little-known and extremely rare 24-year-old liquor with complex butterscotch notes called Martin Mills.

“It’s probably the richest and most memorable bourbon I’ve ever had,” said Char No. 4 co-owner Michael Tsoumpas, a whiskey collector who donated that bottle and several others to the high-end meatery on Smith and Baltic streets. “I’d be shocked if it’s in a bar anywhere else in the world.”

Tsoumpas last sipped the fabled firewater six years ago on a mountainside before The Brooklyn Paper put it to the test this week, with a single ice cube, in the name of journalism.

The dusty bottle — which is one of about 200 released in the world — contains a 107-proof caramel- and vanilla-rich flavor bomb that is best served with some water, “which changes the molecules” and opens up the spirit, Tsoumpas said.

Martin Mills is the name of a fictional distillery, thought-up by Kentucky-based small-batch hootch makers, who bottled the stuff exclusively for sale in Japan in 1999 after they purchased a top-notch bourbon barrel that had matured for more than two decades.

Tsoumpas bought the booze from an obscure retailer in England seven years ago, back when it was the oldest bottle of bourbon anyone could find in the world, he said. Today a bottle would sell for at least $500 — and a single shot at the Smith Street watering hole will set you back $100.

It’s almost unheard of to craft quality bourbon that’s been aged more than 20 years, partly because of the wood-barreling process, which is one reason a sip of the stuff is so pricy.

“A bottle like that can make your place a major destination,” Lew Bryson, managing editor of Whisky Advocate magazine.

Bryson, who tastes brown booze for a living, has never ordered a glass of bourbon that cost more than $60 per ounce. Neither have some of Brooklyn’s most liquor-obsessed connoisseurs: the exclusive River Café’s most expensive drink —a 31-year-old glass of scotch — costs $75 for three ounces, while Clover Club’s 23-year-old bourbon goes for $49 for two ounces.

Whiskey-centric bars often opt not to sell such rare and expensive brands because big-spenders usually prefer to stick with what they know, Bryson said.

“A hundred bucks is a gamble,” he said. “But it’s kind of a fun gamble, right?”

Char No. 4 [196 Smith St. between Warren and Baltic streets in Cobble Hill, (718) 643-2106].

Reach reporter Natalie O'Neill at noneill@cnglocal.com or by calling her at (718) 260-4505.