New Delhi, March 17 -- Thirty years ago, a single light bulb would illuminate the mezcal distillery owned by Gladys Sanchez Garnica's family in rural Oaxaca, where the agave-based spirit was made through the night. As drops dripped from a clay oven, Garnica and her siblings listened to stories told by their parents while neighbors arrived by horse to get a taste of a drink known for its smoky flavor.

"We were taught when to harvest agave, how to care for the soil, and how much we could ask of the forest," said Garnica, 33, speaking from a women-owned distillery in San Pedro Totolapam, a town of just over 3,000 residents in Mexico's Oaxacan Central Valleys, where much of the economy depends on mezcal.

Today, that small-scale tradition ex...