The “mad,” of course, comes from that first distillery; “house” is an homage to Stewart’s 165-year-old Carriage House Farm in North Bend, Ohio, about 20 miles north of Cincinnati. It’s here, in an aromatic facility on the property that doubles as both farm stand and laboratory, that Dean and Stewart test the limits of what ingredients make for a good vinegar. In their alchemy, they’ve incorporated byproducts from local coffee roasters, wineries, an Amish syrup producer, and even a Cincinnati candy company with a surplus of peppermint sticks, all with surprising results. Beyond the malt-based elixirs, MadHouse also produces versions made with locally grown sweet corn and peaches, as well as foraged ingredients such as ramps, spicebush, persimmons, and papaws. These small-batch vinegars show up at some of the area’s best restaurants.