Elizabeth Pearce has written about drinks. She’s lectured about drinks. She’s even sung about drinks. But cocktails are not really her main concern.

“I’m less interested in drinks,” Pearce said, “and I’m more interested in drinking in America.”

Her new walking tour through the French Quarter, launched last May, uses cocktails as a lens to capture the history and the quirks of this imbibing destination. The journey starts at Vacherie restaurant, where everyone grabs a cooler bag filled with four drinks: a Sazerac, a St. Charles Hotel punch, a Hurricane and praline liqueur....