According to labels filed with the Alcohol and Tobacco Tax and Trade Bureau (TTB),  Firestone Walker Brewing Co. will once again be releasing Parabola, a 13.6 percent ABV Russian imperial stout brewed with hallertau and Zeus hops along with nine different malts before being aged in a blend of bourbon, rye and wheated whiskey barrels that have historically been sourced from Elijah Craig, Four Roses, Pappy Van Winkle, Woodford Reserve and Buffalo Trace.

The stout is part of the Paso Robles, Calif.-based brewery’s Proprietor’s Vintage Series and was first released in 2009. In addition, Parabola 2021 will be packaged in 12-ounce bottles with 3,2500 (sic) cases produced.

This may not be the only version of Parabola to released this year, as the Paso Robles, Calif.-based brewery recently filed a label for Double Barrel Parabola, a 15.5 percent ABV imperial stout aged in both bourbon and hated whiskey barrels. Double Barrel Parabola will be packaged in 12-ounce bottles with 450 cases available when it is released.

An email sent to the brewery for additional information was not immediately returned.