A buzzer rings in an apartment of a three-story building in the Mission. A school-age boy with bedhead gets up from the living room couch to prop open the door.
A minute later, Omar Mey, 32, who is from Ticul, Yucatan, walks in from the street. He passes the boy, who's back on the couch immersed in a Spanish soap opera, and sits at the kitchen table, where two other men are busy slurping soup and rolling tortillas.
Dona Carmen (not her real name), a short, thin woman wearing a black apron, turns towards Mey. "What do you want to eat?"
"A cochinita with lots of grease," he says in Spanish, referring to a slow-roasted pork dish native to the Yucatan region in Mexico.
This is how lunch begins every Sunday for Mey and dozens of other immigrants: at Dona Carmen's clandestine pop-up Yucateco restaurant, where strangers sit around and talk about "San Pancho," their nickname for San Francisco. For $8, patrons can expect to eat dishes like relleno negro (turkey stew as black as motor oil), cochinita pibil (slow-roasted pork), and salbuches (chicken-onion soup) with a habanero-based sauce always nearby.
Dona Carmen, who asked for anonymity, is one of about two dozen immigrants operating clandestine pop-up restaurants in the Mission and Tenderloin districts — neighborhoods in which the Yucateco diaspora is concentrated. For many unskilled homemakers, these restaurants are more than a hobby; they are often their only source of income.
Clandestine restaurants like these are at the heart of a hidden sub-community, one among many simply labeled Latino in the city. In fact there are scores of such communities, with different languages, customs, and cuisines.
Yucatecan food, also referred to as "Mayan," is based largely on corn and beans, the most popular crops in the region. Dishes like pibes (a crunchy maize tort stuffed with chicken and a maize sauce) and cochinita pibil are cooked in an earthen pit, which some local restaurants approximate with pizza ovens. Immigrants trace the first Yucateco restaurant in San Francisco back to Tommy's Restaurant in the Richmond, which opened in 1965. Since then, about a dozen legitimate restaurants have opened in the Mission and Tenderloin, with many more of these underground pop-ups to fill demand.
Yucatecan food has not yet reached the mainstream, so that demand is coming exclusively from immigrants, says Caleb Zigas, the CEO of La Cocina, a kitchen incubator that helps low-income people legitimize their business.
It's common knowledge that Yucateco immigrants — most of whom are men between 17 and 29 years old — make the backbone of restaurant kitchens in San Francisco, but when it comes time for them to eat, many prefer the confines of a widow's kitchen over the restaurants where they work.
"The food from the restaurant is frozen food," says Mey, noting that the tortillas at Dona Carmen's are handmade. "You feel like you are at home here."
Dona Carmen tries to be authentic by importing ingredients from Yucatan, like achote, a red paste made of a brush native to Yucatan, and makes her tortillas by hand.
Luis Vazquez, 44, the owner of Chaac-Mool, a Yucatecan food truck, ran a clandestine restaurant of his own out of his old Tenderloin apartment before being discovered by Zigas and forming his own business. He theorizes that Yucatecos prefer to eat at people's homes because they are shy about their eating habits.
"Here they can suck on the bones," Dona Carmen says. "They are humble people."
The practice is illegal, however, as all food made for sale has to be cooked in a commercial kitchen, according to the San Francisco Department of Public Health.
At least one of these underground operations has been closed by health inspectors, but the fact that Dona Carmen's pop-up has avoided authorities for more than 20 years shows the community's ability to insulate itself, says Pedro Tuyub, a former community organizer and owner of Haltun Mayan Cousine Yucateco restaurant in the Mission.
"It's a little bit loyalty, a little bit mistrust of the government," Tuyub says.
He says he doesn't feel threatened by these restaurants. "She is not robbing anyone, she is not hurting anyone. On the government level, I am paying taxes and they are not. That's not important. Everyone has to pay their rent."
Besides, he says, the demand for the food is strong. San Francisco has the highest concentration of Yucatecos living outside of Yucatan, according to Indemaya, a Mexican agency that tracks migrants. The diaspora in San Francisco has swelled from 5,000 to 15,000-20,000 in the last decade.
"That is an example of a natural innovation in the marketplace where there is a demand," says Zigas.
Comida casera, or home cooking like what Dona Carmen makes daily, is very common in Mexico due to necessity, but part of the underground economy among immigrants in the United States. By charging $8 a dish — comparable to restaurant prices — Dona Carmen earns just enough money to pay her $700-a-month rent, she says.
This practice is known as income patching, Zigas says. "The benefit of income patching is that it lets you do what you want. If you have kids and need to be home, you can do that."
Dona Carmen started her restaurant out of boredom 20 years ago. "When I first arrived, my kids did not want me to look for work," she says. "I wanted to work."
Her situation changed. First her husband died, and then her children formed families of their own and could no longer pay for her rent. Now that she is over 60, she finds it daunting to find a job. "Now that I am alone I can't work in a restaurant," she says. "No one hires you after 50."
Back in her kitchen, Mey greets two other men he knows. They start speaking Yucatec Maya. It's the usual lunchtime chatter: hangovers, their bosses, soccer games.
"Everyone walks in talking gossip," Dona Carmen says. "That's what life is like in San Pancho."