What is the "root" in "Root Beer"?

Currently, root beer is made from extract in a syrup..
However, historically, it was made from ground sarsaparilla roots.

A combination of roots and more, actually. Hires’ original recipe included:
Birch Bark
Chirreta
Dog Grass
Ginger
Hops
Juniper Berries
Licorice
Sarsaparilla
Sugar
Vanilla
Wintergreen
Yerba Mate

@ PT that sounds delicious. I started drinking virgils recently and that is very good. Has a lot of the ingredients you just listed.

Cliff Claven moment: it actually started out as “root tea,” but became “beer” to increase sales among laborers.

NORM!

@Kevbo: Anybody who quotes Cheers is okay in my book.

Ginger “ale”, and its cousin ginger “beer” were also originally brewed.