Tonight, Goose Island Brewing Co. is releasing A Real Nice Surprise, a porter aged in rum, bourbon and brandy barrels for two months.

The beer is brewed with a blend of malts consisting of 2-row, Carapils, chocolate malt, Munich 2, naked oats, roasted barley, and Simpson Golden, as well as Fuggel and Northern Brewery hops. It clocks in with an ABV of 8.3 percent and 24 IBUs.

It’s part of Fulton & Wood Series, a compilation of employee-driven beers made in small batches. The brewery is located at W. Fulton Street and N. Wood Street.

A Real Nice Surprise was inspired by two holiday classics: eggnog and “National Lampoon’s Christmas Vacation.” It will only be available in 1/6 barrel kegs in the Chicago area.