Bajoran ale was a type of ale created by the Bajorans.
Although Quark sold it, he found it hardly potent at all, and claimed that one should "never trust ale from a god-fearing people." (DS9: "Emissary")
Constable Odo, after being turned into a Solid by the Founders, found the fizzing sound of bubbles in beverages such as Bajoran ale seductive. Before he was a Solid, he never paid any attention to such characteristics of food or drink. Odo enjoyed a Bajoran ale when approached by Benjamin Sisko in 2373. (DS9: "Apocalypse Rising")
Odo's drink is identified as Bajoran ale in the episode's script. 
Quark offered the exhausted Kira Nerys a frosty Bajoran ale or a black hole in 2373, but eventually brought her warm Enyak's milk to help get her to sleep. (DS9: "Ties of Blood and Water")