There are a lot of ways to barrel age a beer. Sometimes unfermented wort is racked directly into barrels. Sometimes fermented beer is added and then allowed to age. And then there’s the happy medium: Allowing the beer to ferment in the barrel and seeing what magic happens.

That latter path is the one River Dog is currently taking. On Tuesday, they posted a photo of barrel fermentation in progress inside two barrels at the brewery. No word on what beer is in the barrels or what the barrels are, but it should be noted River Dog has a proclivity for Maker’s Mark barrels.