Eelwasser
Eelwasser was a type of Ferengi beverage. Its primary competitor was Slug-o-Cola.

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. ()

Appendices

Background information 
Curiously, the bottle featured a label with the Vulcan IDIC symbol.

According to Legends of the Ferengi (written by two of s writers, Ira Steven Behr and Robert Hewitt Wolfe), Eelwasser was discovered by two boyhood friends named Sluggo and Vorp. Sluggo tricked Vorp into drinking bog water, and was surprised when Vorp commented, "Mmm. Tastes like eel."

Wasser is German for water and, as such, is used as a suffix in a number of drinks (not just water types) in the language.

An advertising jingle for Eelwasser was included on the Legends of the Ferengi audiobook.

External link 
 

de:Eelwasser
nl:Eelwater
Beverages
Ferenginar