Brooklyn Brewery’s Garrett Oliver is among those in the beer industry who also love a good cocktail.

Oliver, Brooklyn’s longtime brewmaster and editor of “The Oxford Companion to Beer,’’ is as enmeshed in beer as you can get. And yet, several years ago, Brooklyn pioneered the cocktail-inspired beer — brewing the Manhattan Project to taste just like its namesake drink, made with whiskey and sweet vermouth. Oliver credits relationships with bartenders and cocktail writers for piquing his interest in mimicking a cocktail with a beer recipe.

“I have a great window into that world,’’ says Oliver. “Cocktail culture is endlessly creative. In the cocktail world, it’s possible to try 20 variations on a recipe in a single afternoon, so the evolution of combinations is rapid.’’

With those many variations come more chances to make mistakes, something Oliver was well aware of when making Brooklyn’s latest cocktail-inspired beer, Improved Old Fashioned.

“It’s a challenge to do it well,’’ he says, “and if done well, it’s delicious.’’

Brooklyn’s approach to the Old Fashioned is not dissimilar to a bartender’s when making the original for you. The base is a strong rye beer, suffused with spices and fruit peels and then aged in WhistlePig Rye Whiskey barrels.

Bartenders have been tinkering with Old Fashioneds for years, adding the likes of absinthe or maraschino liqueur to a base drink consisting of whiskey, sugar, and bitters. In the case of Brooklyn’s beer, there’s some Belgian candi syrup, orange and lemon peel, nutmeg, cinnamon, coriander, gentian root, and cloves, all added to the strong ale of 12.8 percent alcohol by volume.

“I take the drink seriously,’’ says Oliver. “Like an omelet, it’s both simple and easy to mess up. Of course, you want to get the flavors and aromatics correct, but then there’s the tension between bitterness and sweetness that really needs to be finely tuned. I think we capture those really well.’’

Brooklyn’s Improved Old Fashioned drinks decidedly like a beer — it’s heavier than the cocktail and lacks the alcohol burn — but everything else is there. Close your eyes and you’d think you were smelling a just-emptied whiskey barrel. The beer is booze-strong, and the balance between sweet and tangy is just right.

Try Improved Old Fashioned and other Brooklyn offerings when the brewery’s Mash tour comes to Boston Oct. 13-16. For more information or to purchase tickets, go to www.brooklynbrewery mash.com. Gary dzen

Gary Dzen can be reached at gary.dzen@globe.com. Follow him on Twitter @GaryDzen