Bricia Lopez is the mezcal queen of Los Angeles. Five years ago, Lopez, who is thirty-one and imposingly savvy, persuaded her father to let her build a mezcal bar at Guelaguetza, the restaurant that he opened when the family moved north from Oaxaca, a center of mezcal culture, in the mid-nineties. He didn't know if Americans would like mezcal, or if Mexicans would admit that they did.