Root Beer

Root Beer is a human beverage, which is centuries old but still very common and popular among humans. It is the non-alcoholic substitute of beer with the same sort of taste. Since servicemen on active duty in the UNSC are prohibited from drinking alcohol, because it clouds the thinking of humans and most other species (much the way the inhalation of Benzene clouds the thinking of Grunts), this beverage serves as a decent-tasting virgin (non-alcoholic) drink. Alcohol consumption could be a very serious issue in times of conflict, hence why the root beer beverage is so popular on UNSC ships. It is a standard choice on Food & Drink Dispensers, which are themselves standard throughout the UNSC Navy.

Trivia
Root Beer is on the menu for drinks in the pillar of autumn's mess hall.