A local is releasing a barrel-aged porter exclusively at its taprooms.

Grand Rapids-based Founders Brewing Co. is rolling out Panther Cub as the fourth release in its taproom-only Mothership Series.

Panther Cub is also the first barrel-aged release of the series. It will be available in the brewery’s Grand Rapids and Detroit taprooms in six-pack bottles and on draft beginning Dec. 1.

Panther Cub is a porter aged in a combo of BLIS maple syrup bourbon barrels and regular bourbon barrels for over two years, with whole vanilla beans, yielding tasting notes of maple and vanilla.

While Panther Cub has been featured in the taprooms a handful of times, this marks the first time it will be available in bottles.

Founders’ Mothership Series also includes Red’s Rye IPA, Sleeper Cell and MF Donkey Stout.