Remember when you thought drinking a root beer could get you drunk? Fast forward about 25 years: now root beer actually can get you a little tipsy. Three Olives Vodka has added yet another flavor to their repertoire: root beer. The original root beer dates back to the 1860s, when a Philadelphia pharmacist mixed vanilla, cherry tree bark, licorice root, sarsaparilla root, nutmeg, and molasses, then tried to sell it as a miracle elixir. But Three Olives’ version will probably do a better job of curing your ills (at least temporarily, anyway). Its sweet flavor has a hint of mint and is smooth enough to drink on the rocks. But we recommend the Root Beer Floatini — a combination of the flavored vodka and amaretto, shaken and served with a mini scoop of vanilla ice cream. It’s the adult version of the drink we used to love during our pigtails-and-overalls days. If that’s a little too juvenile for your oh-so-adult tastes, opt for some Brotherly Love, a simple mixture of root beer vodka and lemon-lime soda over ice. This British-born vodka is served on our side of the pond at the Good Life (28 Kingston Street, Boston, 617.451.2622); it’s also available by the bottle ($19.49) at Blanchard’s Liquors (103 Harvard Avenue, Allston, 617.782.5588).