Almost exactly one month after this year’s version of Surly Brewing Co.’s Pentagram shipped, information has surfaced about a variant that is being worked on.

According to filings with the Alcohol and Tobacco Tax and Trade Bureau (TTB), the Minneapolis, Minn.-based brewery will be releasing Barrel-Aged Pentagram, a 9.4 percent ABV dark sour ale brewed with 2-row pale, Belgian crystal, chocolate and dark Munich malts as well as Columbus hops before being aged in red wine barrels sourced from California for 18 months. However, this version of the ale has been aged in rye whiskey barrels for an additional period before being bottled.

Surly has released a barrel-aged version of Pentagram before in 2014, but that version was a draft-only option aged in High West rye whiskey barrels and came in at a lower 6.7 percent ABV.

Barrel-Aged Pentagram will be packaged in 750ml bottles. An email sent the brewery was not immediately returned.