Upslope Brewing Co. is continuing its Lee Hill Series with its newest release.

The Boulder, Colo.-based brewery has released Lee Hill Series: Vol. 3 Barrel Aged Imperial Stout, a 10 percent ABV imperial stout that has been aged in Leopold Bros. Maryland-Style Rye Whiskey barrels for four months. According to the brewery, the beer incorporates Maris Otter, caramunich 3, special b, chocolate malt, roasted barley, and dehusked carafe II malts along with English East Kent Golding and American cascade hops.

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The newest release is part of Upslope’s Lee Hill Series, which commemorates the original brewery location at Lee Hill in Boulder, Colo.

“Upon building a second Boulder brewery, our plan was to retain our original location at Lee Hill to continue the legacy of innovation, collaboration and experimentation that has brought us to where we are today,” said Matt Cutter, Upslope’s founder, on the company’s website. “The introduction of the Lee Hill Series allows us to showcase the best of what has emerged from this brewer’s playground.”

To date, there have been two other releases in the Lee Hill Series: Vol. 1: Barrel Aged Brown Ale, a 7.6 percent ABV brown ale also aged for four months in Leopold Bros. rye whiskey barrels and Vol. 2: Wild Saisona 6.8 percent ABV saison that was aged for seven months in red wine barrels and was brewed with both lactobacillus and brettanomyces.

About 1,200 19.2 ounce cans ($10) of Lee Hill Series: Vol. 3 were released at an event on Feb. 19 at the Lee Hill tap room in Boulder, Colo. with any remaining cans distributed “to select liquor stores in Colorado the week following the brewery release.”