Deep in the northern Oaxacan countryside, Don Julio Isidro, 69, emerges, smiling, from a stand of trees on the banks of the Usila River. In one hand he holds a machete; in the other, a slender tree branch, quickly split to form a sort of oversized pincer. He hands the giant tongs to Don Victor Santiago, another of the village elders, and they exchange a few words in chinanteco, one of the last indigenous languages of Mexico.
Don Victor takes care of a raging fire of orangewood planks, which conceal a few dozen carefully selected river stones inside. Balancing on the rocky shore next to the fire are several jicara, or large gourds, each filled with aromatic vegetables, herbs, cold water and a half mojarra, a freshwater fish resembling tilapia. Soon Don Victor will be using the tree branch tongs to move the glowing fire stones into the gourds. Their fiery heat will transform the assorted ingredients into an ancient dish called caldo de piedra (literally: stone soup): broth cooked not over a fire, but by a hot stone.
Said before the arrival of the conquistadors, caldo de piedra is now famous enough to be on the menu of white tablecloth restaurants like El Lago in Mexico City and Casa Crespo in Oaxaca. But his roots are here, in the small Chinese town of San Felipe Usila, where he remains a fundamental part of life despite the fact that the world around him has changed.
“Usila has all the riches that God gives us, and the people of Usila use everything,” says Don Julio, explaining that all the ingredients for the soup were here by the river. Some men (until recently the soup was made exclusively by men) picked stones from the river while others gathered firewood and fished for shrimp and mojarra. The cooks were picking up tomatoes, onions, peppers, garlic and herbs from the nearby gardens, and not far from where I’m sitting by the river I can see the jicara tree, bright green gourds that turn into bowls hanging heavily from its branches like oversized Christmas decorations.
Today it’s different: a dam built 20 years ago has decimated the local population mojarra supply, so the Usileños now have to travel to the next town to buy fish. Families carry five-gallon bottles of purified water to shore, fearing the water in the river is no longer clean enough to cook. And instead of using a stone to crush garlic and tomatoes, some cooks now use graters or even electric mixers to get the job done. Corn caldo de piedra always plays a vital role in family gatherings, especially during Semana Santa (Holy Week) when the riverbank is crowded with groups of people each preparing their version of the dish.
After half an hour in the fire, the stones are ready to be placed in the calabashes, one for each member of our group consisting of family, neighbors and guests. Don Victor uses the pliers to gently guide the first rock into the first jicara. Right away, the broth begins to spit and foam against the white-hot stone, sending the heady aroma of garlic, cilantro and chili peppers into the river.
Each gourd swallows three or four stones before the soup is ready to eat, and the worn stones are removed before serving. From the first sip, the soup is intoxicating: spicy, smoky, tasty and tinged with mineral notes from the rock. We eat, bending over our gourds, squatting on the shore. I sit on a rock near Lalo Lozano, a Usileño from a generation younger than the elders who begins to speak poetically about the importance of the dish to the Chinantec culture.
“It’s identity, it’s harmony, it’s family,” says Lozano. “It is our responsibility to teach the children, so that this does not go away. “