Side Project Brewing’s Derivation Blend #5 is being released today, but there is a twist.

The beer is a stout brewed with Ugandan vanilla and coffee sourced from the Cajibio, Caldono, Morales, Peindamo and Torbio regions of Colombia by St. Louis-based Sump Coffee before being aged in rum barrels. This is the first rum barrel-aged beer that Side Project has released, and unlike the previous four incarnations of the beer, the newest version is only available to drink on-site, with no bottles being sold to go.

Side Project Brewing on Twitter

Derivation Blend 5 starts today at @sideprojectcell at 3pm. ON SITE ENJOYMENT ONLY. pic.twitter.com/jVQSZBGnOq

According to a post on Sump Coffee’s website, the specific coffee that is incorporated into the beer is the same varietal that Perennial Artisans Ales used for its regular Sump Coffee Stout  (10.5 percent ABV) release this year. However, both companies used different methods of coffee extractions to achieve what they were looking for, with Perennial using a toddy and Side Project utilizing the whole bean for its beer.

Derivation Blend #5 is packaged in 750ml bottles and will go on sale today at The Side Project Cellar for on-site consumption only.