How New York City’s First Heirloom-Focused Tortilleria Is Preserving Mexico’s Native Corn

Like the alchemy of acid and fat, the balance of sweet and salty, and the classic pairing of peanut butter and jelly, two is so often better than one in the world of food. This is Culinary Duos, a series by senior culture editor Megan Zhang spotlighting dynamic pairs—from couples to siblings to friends—whose partnerships produce flavor-filled magic.

Shared love of tortillas is what brought together Zack and Diana Wangeman—who met as high schoolers in Oaxaca, Mexico—as partners in business and life. In 2021, the duo opened Sobre Masa, a new restaurant, retail shop, and heirloom tortilleria in Brooklyn’s Bushwick neighborhood and the first in New York City to work strictly with imported heirloom corn.

As a child, Zack became fascinated by the chemistry behind how and why ingredients work together, and he dreamed of one day becoming a pastry chef. So, in 2010, he left Mexico and moved to Manhattan, where he attended culinary school and worked at the restaurants Jean-Georges and Per Se. Meanwhile, Diana earned her medical degree back in Oaxaca, then worked part-time as a physician and the rest of the time in her mother’s restaurants. Over the years, Zack and Diana stayed in touch and caught up once or twice a year whenever Zack returned home to visit. “She’s probably one of the only people from high school that I actively kept in touch with,” he recalls. “We had a special relationship.”

In 2018, Zack began cooking Oaxacan food in a pop-up called Comadre Cocina that eventually found a permanent home in the now-closed Brooklyn brewery Folksbier. Dishes like mole almendrado, garnachas, and chorizo were his answer to the growing nostalgia he felt for the cuisine of his home region. “[The pop-up] really allowed me the freedom and the platform to do whatever I wanted,” says Zack. As much as possible, he took care to prepare ingredients from scratch, making queso fresco and drying herbs himself. 

One of the more elusive elements to his set-up was a key pillar of the whole operation: high-quality tortillas. In New York City, Zack struggled to find ones that were made with Mexican heirloom corn, or captured the flavor and essence of the tortillas he had grown up eating. “The smell is the thing I look for the most,” he explains. “You just get that aroma of, like, popcorn”—worlds apart from the faintly sour scent of most store-bought tortillas, which usually include preservatives that increase their shelf life and make them harder and drier. Perhaps, Zack thought, he could make them by hand himself. So he bought a mill and began practicing the science and art of nixtamalization.

“Good masa comes from nixtamalization,” he explains, referring to the intricate process of cooking corn kernels in an alkaline solution of calcium hydroxide, which not only breaks down the skin and makes the nutrients available for absorption, but also gelatinizes the starches and encourages pliability. The corn is then ground into masa, which is pressed into tortillas. “Good masa will only ever have three things: calcium hydroxide, water, and corn,” he explains.

When Zack returned to Oaxaca, he visited Diana to chat with her and her mother about nixtamalization and heirloom corn. If anyone in his community knew a thing or two about it, it was her family. Many farmers in Diana’s home village of Teotitlán del Valle have been growing corn for generations and continue to follow traditional cultivation techniques.

Growing up, Diana observed people implementing ancient agricultural methods like milpa, a practice that involves growing corn, squash, and beans together in what Zack calls a “symbiotic relationship”: the beans climb up the corn, while the squash provides cover for the soil. Crop diversity also helps enrich the soil, unlike the single-crop system that most agricultural corporations adopt, which can force soil to develop a dependence on fertilizers. Other methods Diana saw as a child in her village can only be explained as well-practiced intuition: “My grandparents, they just see the sky, and they’re like…‘It’s time to start planting the seeds,’” she says, explaining that farmers time this step to just before the start of the wet season.

The ancient wisdom behind heirloom corn cultivation in Mexico and the complexities of nixtamalization and tortilla-making fascinated Zack. Whenever he returned to Oaxaca, he would observe and learn from Diana’s mother while she made tortillas.

In September 2019, Zack left Folksbier to take some time off in Mexico. But in March 2020, his mother passed away, and the beginning of the pandemic forced everyone to shelter in place. As time in quarantine wore on, his mind kept returning to the idea of opening his own business, which the success of Comadre Cocina had encouraged him to consider. In the wake of a family tragedy and in the midst of a global pandemic, working on a project gave him hope and something to look forward to. He began putting together a business plan for a tortilleria and, in May 2020, moved back to New York City.

A few months later, Zack opened Sobre Masa as a pop-up selling tortillas in Williamsburg, while he looked for a more permanent home for the operation in Bushwick. In December of that year, Zack suggested to Diana that she should come to New York to help him. She agreed and flew to join him, but the city shut down indoor dining shortly after, and the pop-up had to close. Throughout that winter, Zack and Diana focused on selling tortillas wholesale. “It was just the two of us pressing tortillas the whole day,” she recalls. 

In October 2021, Sobre Masa finally opened the doors of its permanent home in Bushwick. 

Zack and Diana wanted to make tortillas in a way that tasted like home, and they also wanted to “be a voice for corn,” says Zack. So they began working with Tamoa, a Mexico City-based company that sources surplus production of heirloom crops from small farms in Mexico and sets up supply networks that help generate income and opportunities for these producers.

In recent decades, an array of challenges have endangered the preservation of Mexico’s native corn varieties. US-imported corn flowed into the country after the implementation of the North American Free Trade Agreement in 1994, taking business from small local growers. Because flour brands wanted white corn, farmers cultivated less and less of the varieties that exhibited other colors. But Mexico’s heirloom corn has deep-rooted cultural value—not to mention environmental wisdom.

Mexico is home to dozens of native corn varieties that have been cultivated for millennia—inherited, guarded, and preserved by each subsequent generation. “These crops are the livelihood and identity and culture of an entire territory and country,” says Tamoa’s co-founder Francisco Musi. Corn is the backbone of Mexico’s foodways and has nourished countless generations of Mexican people. “It’s because all our ancestors, especially in Mexico, just took such good care of nurturing this plant,” adds Zack. “It’s been woven into our everyday lives.”

The flavor, nutritional value, and hardiness of heirloom corn, Musi explains, greatly surpass those of its mass-grown counterparts, which are specifically bred to achieve high yields. Those resulting profits can come at a cost: soil erosion, loss of genetic diversity, and other ecological damage.

“Heirloom seeds have an innate capacity of adapting. That’s what they’ve been doing throughout history,” explains Musi. “They’re very in tune with the environment and their surroundings.” Corn was traditionally irrigated by rain in Mexico, so the plants had to adapt to volatile weather conditions. After each growing cycle, the seeds that survived were the ones farmers sowed the following season. Over millennia of selection, heirloom seeds have evolved to be hardy, resilient, and genetically diverse. “There are all these different varieties that are designed to thrive in that particular [environment],” adds Zack. “This diversity is important to promote and protect.”

The genetic fitness of these seeds resulted from the ancient wisdom of generations of stewards, and strengthening these farmers’ sovereignty is critical for preserving native crops. “They can really be the agents of change for the future,” he says, referring to heirloom growers and their instincts for how to best nurture the land. Many of these small-scale producers also utilize sustainable agricultural approaches that protect the environment, like relying on natural compost over chemical fertilizers. By advocating for heirloom farmers, customers like Sobre Masa can help sustain heirloom seeds, build awareness around their ecological and nutritional value, and promote their stewards’ eco-conscious practices.

At Sobre Masa, Zack and Diana make an effort to educate customers about the value of Mexican heirloom corn and the stories behind them. The menu shares the rotating varieties’ names and places of origin so customers can learn more about the diversity of Mexico’s native corn. Because different types of corn behave differently during nixtamalization and milling, Jesus Perea, who handles all the tortilla-making at Sobre Masa and is now a co-owner, tweaks the steps for each variety. After pressing the masa into tortillas, Perea cooks them halfway before they are sold to customers. “That way, when they buy our tortillas and [warm them] at home, they have the privilege of seeing their tortillas being inflated,” he says. They come in a rainbow of natural colors—white, yellow, pink, and blue.

Today, the reality of Sobre Masa is a little different than the tortilla factory Zack and Diana envisioned back in 2020. During the day, the brick-and-mortar shop also sells masa, pastries, coffee, and other products, before the restaurant portion opens in the evening and serves cocktails, flan, and of course, tacos topped with al pastor, bistec, or cauliflower. The team now makes 4,000 to 5,000 tortillas a day—and Zack and Diana’s friendship has also evolved. “We were spending so much time together and, [even] more special, building something together, where you could see roots and you could see growth,” says Zack. “It just seems natural something would eventually blossom.”

Perhaps a shared goal is what it took to turn their spark into a flame. Sobre Masa’s mission of honoring and bolstering the heirloom seeds and farmers of Mexico continues to motivate the two, who are now married.

The Spanish phrase “sobre masa” translates as “about masa,” but the name is also a play on words: “Sobremesa is a conversation you have after dinner,” says Zack, describing the communion and repartee that often lingers long after meal companions have finished eating. The name captures the sense of community that Zack and Diana are seeing develop around the preservation of Mexican heirloom seeds, and they hope that enthusiasm continues to grow.

Sobre Masa recently broke its record of most corn cooked in a single day: 275 pounds, which will produce 500 pounds of masa. If the restaurant’s growth is any indication, the future of heirloom corn is looking up.

“We have unconditional, unlimited blind faith that the best is yet to come,” says Zack.