Eelwasser was one of the most popular beverages in the Ferengi Alliance. It was first discovered by Sluggo and Vorp when the former tricked Vorp into drinking fetid bog water out of the Bowog Bog. Vorp found it to be delicious, remarking "Mmm. Tastes like eel."
Mass production and marketing of Eelwasser began soon after, in bottles featuring the faces of both Vorp and Sluggo on the label. For four decades, Eelwasser was the dominant beverage in the Ferengi marketplace, faltering only after a consortium of rival beverage makers developed Slug-o-Cola, and enticed Sluggo to become its spokeperson. Eelwasser's market share fell to under thirty percent as a result. (DS9 novel: Legends of the Ferengi)
In 2374, Eelwasser was reporting excellent profits, while Slug-o-Cola was doing quite badly. While posing as Lumba, Quark told Nilva that supporting Grand Nagus Zek and allowing equal rights for females would give Slug-o-Cola an edge over Eelwasser. (DS9 episode: "Profit and Lace")
Shortly after, Ferengi Commercial News predicted that Eelwasser was on its way to victory over Slug-o-Cola, which they predicted would soon be out of business. (DS9 novel: Ferenginar: Satisfaction is Not Guaranteed)
In 2376, the Eelwasser company joined forces with Brunt and Chek Pharmaceuticals to depose Rom. In his advertisements, Brunt claimed he now drank only Eelwasser and would make it the official beverage of the Nagal Residence. It was later revealed Eelwasser was involved in a conspiracy which involved the forging of a marriage contract. Eelwasser stock fell dramatically in the aftermath of this revelation. (DS9 novel: Ferenginar: Satisfaction is Not Guaranteed)