Downtown Napa had its power on Wednesday, but just two blocks to the south of the upscale restaurants, the working-class Abajo neighborhood was in the dark and hurting.

Some found refuge at La Tapatia Market, a neighborhood Mexican grocery store that lost power — along with more than 141,000 other PG&E customers across the Bay Area — but stayed open anyway. A small generator hummed near the front door, providing energy to a freezer where the ice cream was doing its best to remain solid.

“We’re trying to help the neighborhood,” said manager Tony Parra, 36. “People might be out of power for a few days. We’re staying open mostly for them.”

Shoppers walked the aisles in near darkness, guided by glints of sunlight that crept in the open doors. They made their way through dim rows of Mexican sodas, star-shaped pinatas and stacks of cowboy hats and woven blankets.

By flashlight, workers moved the store’s supply of beef brain, cow feet, beef cheeks, tripe and other meats onto ice while others did their best to keep the beer cold enough to drink. Posters of the Virgin Mary and the Last Supper kept vigil from the wall

“People are showing a lot of appreciation — they’re saying nothing (else) is open” Para said, as two checkers added up customers’ orders on their calculators. Sales were cash only without power.

Pat Ayala stopped by to pick up some ice after losing power around midnight. She admitted she wasn’t prepared. Her mother, who lives with her, needs electricity to power the machine she uses to treat her asthma and to keep her insulin cool in the refrigerator.

“It’s crazy,” Ayala said. “I really don’t know what I can do.”

Greg McLean, 45, said he lives nearby and stopped by for canned menudo, because “everywhere else was sold out.”

He was ready for the outage, putting all his meat in a deep freezer loaded with ice.

“Hopefully, that will last a couple of days,” McLean said.

Evan Sernoffsky is a San Francisco Chronicle staff writer. Email: esernoffsky@sfchronicle.com Twitter: @EvanSernoffsky