Espita Mezcaleria, a new bar in Washington, stocks more than 130 kinds of mezcal. But Megan Barnes, the beverage director, has a surprising sales technique when customers ask for certain brands.

“A lot of people come in and say, ‘I only want something that’s grown in the wild,’” she said. “We try to steer people away from those, because if you’re constantly drinking these wild agaves, you’re depleting the wild agave fields in Mexico, and then there’s nothing left. We try to teach our customers to be responsible, and we’re responsible ourselves.”

Here, in a shot glass, is the current quandary mezcal drinkers face in the United States. Never has the liquor — tequila’s smokier, rougher parent spirit — been more visible, plentiful or popular. Barely a month passes without a new mezcal bar opening in some American city; recent arrivals include Madre Mezcaleria in Brooklyn, Quiote in Chicago and Coyote Mezcalería in Portland, Ore. That’s a great thing for a beverage that has long been misunderstood and underappreciated by Americans.