While they aren't describing a literal bar, drinking root beer at the disco ... As their leader, Snoopy is frustrated by this ...

Snoopy misses Woodstock so much that he forlornly sculpts an image of him out of root beer foam. Many of the shorts celebrate Snoopy’s ability to transport himself outside of reality.

A five-strip sequence exhibited in the show follows the scouts when they ditch Snoopy to go to town for night of disco and root beer. Woodstock returns to report to Snoopy that Harriet is in jail.

Besides, if it's good enough for Snoopy to quaff while he's roaming the French countryside as a World War I flying ace, it's good enough for you. But why is it called root beer? Did it ever ...