Here's the thing about gin: It's almost never a sipping spirit.

Sure, it's a key component in cocktails, from the classic G&T to the Negroni. But very few modern-day tipplers would consider ordering a glass of gin on the rocks. A crop of new barrel-aged gins, however, could change that.

These gins—aged in whiskey, brandy or rum barrels—are still gins at heart. They have the essential juniper flavoring and other botanicals, too. But time spent resting in oak gives these gins a golden cast and smooths over sprightly botanical notes with light layers of vanilla, maple and brown sugar. The end result is an enticing vanilla spice that still lends itself to cocktails but is also mellow and nuanced enough to sip straight. Here are six bottles to look out for.

Chief Gowanus New-Netherland Gin (New York Distilling Company, Brooklyn, NY): Cocktail historian David Wondrich collaborated with Allen Katz's New York Distilling Company on this barrel-aged version of "Holland gin," drawing inspiration from the days when New York was still Dutch. It has a touch of hops thrown in, which adds a zesty, citrusy note. At The Shanty, the bar adjacent to the distillery, it's served in the Stomp & Swerve cocktail with Amaro Meletti, orange liqueur and lemon.

Citadelle Reserve Gin (Citadelle, France): Alexandre Gabriel of Cognac Ferrand has experimented with different variations of barrel-aged gin since 2008. The 2013 edition employs three different barrels and is aged using the solera method. The end result is relatively pale in the glass, fresh and lightly scented with vanilla. It's civilized in a Martinez cocktail.

Corsair Distillery Barrel-Aged Gin (Corsair, Nashville, TN) : The guys at Corsair are known for their crazy small-batch experiments (hello, twelve-grain whiskey), so it's only natural that their limited-edition gin is different from what anyone else is doing. Aging their gin in twice-used Corsair Spiced Rum barrels gives a pumpkin-spice effect with distinct cinnamon and nutmeg notes. Serve with ginger beer in a tumbler full of ice.

Smooth Ambler Barrel-Aged Gin (Smooth Ambler, Maxwelton, WV): Rested in used bourbon casks, then bottled at a striking 99 proof, Smooth Ambler's gin still retains a frisky botanical nose, vanilla/burnt orange notes and a buttery feel. Try it with lemon and simple syrup for a lighter take on a whiskey sour-style cocktail.

St. George Dry Rye Reposado Gin (St. George Spirits, Alameda, CA): In tequila talk, reposado means "rested"—aged in barrels for anywhere between 60 days and one year. This unusual, rosy gin is made from a rye base, infused with gin botanicals and "rested" for 18 months in casks that previously held Syrah and Grenache wines. (So technically, this should be anejo, not reposado, but who cares when the end result is this malty and oaky, with a fleeting notes of dark fruit?) All it needs is a splash of sweet vermouth.

Waterloo Antique Barrel Reserve Gin (Treaty Oak Distilling Co., Austin, TX): Aged in former bourbon barrels, this is one of the darker aged gins on the market, with a deep tawny hue and bold brown sugar flavors drying into chamomile tea, cedar and clove on the finish. It makes a dynamite variation on a Manhattan.