Recently my brother Chris brought me a bottle of Root, a liqueur made by Art in the Age, a small Pennsylvania storefront mingling art, music and some unique beverages. (They also make Snap, with ginger, and just released a new product called Rhuby, with rhubarb prominent among a chorus of other ingredients.) Root has cane sugar and roughly a dozen different flavorings, including birch bark, cardamom, allspice, sassafras and wintergreen. We tried a bit neat, but the revelation came when it was mixed with seltzer - voilà: adult root beer. (Yes, there's a recipe that calls for a scoop of vanilla ice cream.)
Later I introduced Root to four friends, expecting only one to be brave enough to even try it. (A casual survey suggests that root beer is not as universally loved as I'd imagined.) To my surprise, all four found it delicious.