BELÉM, Brazil — To start things off right at Thiago Castanho’s laboratory of Amazonian culinary revelations, take a sip of his signature cocktail, which blends cachaça, made from sugarcane, and jambu, an herb with analgesic properties whose flowers look like yellow and pink eyeballs. Sit back and let the jambu create a pleasant tingling sensation on the tongue.
Then on to the food. Try the cassava flat bread with dried shrimp, or a cheese made from the milk of water buffalos from Marajó, an island at the mouth of the Amazon River. Move on to plates like smoked mapará, a fish that tastes like eel, and then finish things up with a dessert of cupuassu fruit prepared with a sprinkling of flour made from manioc and the fruit of babassu palms, and Mr. Castanho’s ambitions grow clear. He wants to show the world that a bounty of little-known ingredients found in the Amazon has the potential to turn the cuisine of Latin America’s largest nation on its head.
“When people think of the Amazon, they envision the expanses of rain forest, maybe some settlements here and there,” said Mr. Castanho, a reserved 26-year-old who dresses like a surfer and speaks almost in a whisper.
“They forget that human beings have lived in the Amazon for thousands of years, experimenting throughout that time with the ingredients at their grasp,” he said in an interview at his restaurant, Remanso do Bosque. “It’s a little subversive, I know, but I think it’s time for the rest of the world to be exposed to some of these sublime creations.”
A more conventional route for an ambitious Brazilian chef would have been to open yet another restaurant in São Paulo, Brazil’s largest city and dining capital, where tattooed celebrity chefs have gathered in such large numbers that Julio Bernardo, an acerbic food critic and blogger, is gaining celebrity status for taking them down a notch.
But while Mr. Castanho studied at a culinary school in Campos do Jordão, an outpost of faux-Swiss chalets in the hills of southeast Brazil, he opted to return to his home city, Belém, a bustling Amazonian river outpost with a metropolitan population of 2.2 million more than 1,500 miles to the north of São Paulo’s concrete canyons.
Mr. Castanho has become one of Brazil’s most innovative chefs as he pioneers a culinary renaissance in Belém, a once-thriving center of the Amazon rubber trade that went into a long decline in the 20th century, remaining a backwater in the view of many Brazilians.
“Thiago comes around here some days, always bargaining for the freshest catch,” said Brasiliana da Silva, 53, a fishmonger in Belém’s riverside market, the Ver-o-Peso, where boats yield offerings each morning around 4 such as tambaqui, the large omnivorous freshwater fish whose barbecued ribs alone make a succulent feast.
“No one is more curious or demanding than Thiago,” Ms. da Silva said. “He’s always looking for something new.”
Few places in Brazil offer the fixings for terroir cuisine quite like Ver-o-Peso, named for the large scales on which harvests from points across the Amazon are weighed. Here, fish of all shapes and sizes are sold next to rain forest fruits like the sweet-and-sour tasting bacuri (resembling a rounded papaya) or the greenish egg-shaped uxi.
Ver-o-Peso is also where Mr. Castanho comes to buy açaí, the dark purple berrylike fruit which is a staple in this part of the Amazon. Before dawn each morning on the market’s cobblestone wharf, wholesalers sell baskets of fresh açaí harvested by families in villages near Belém.
While beachgoers in Rio de Janeiro generally consume açaí in smoothies, mixing its frozen pulp with sugar or other sweeteners, Mr. Castanho hews to tradition here, using the fruit to make an unsweetened thick cream with an earthy taste, or combining it with manioc flour to sprinkle on fresh fish.
Beyond the market, the inspiration for many of Mr. Castanho’s dishes comes from the streets of Belém, a four-century-old city where the jungle constantly seems to be seeking to reclaim its dominance.
So many mangoes, for instance, drop from Belém’s trees that drivers complain of mechanics profiting from repairing cars damaged by falling fruit. Vines envelop abandoned graffiti-splattered colonial homes, making it seem as if parts of the city have been allowed to evolve into elegant ruins even as contemporary high-rises soar above them. Mr. Castanho grew up in the lower rungs of the restaurant business, delivering pizzas for his father’s pizzeria in Belém. But he was immersed in Belém’s cooking traditions when his parents opened Remanso do Peixe, a restaurant serving food from Pará, the immense Amazonian state that is almost twice the size of Texas.
After attending culinary school, Mr. Castanho moved across the Atlantic to Lisbon to work for Vitor Sobral, the chef known for reinvigorating Portuguese cuisine, before returning to Belém to open Remanso do Bosque.
Eating at Remanso do Bosque isn’t cheap. But while its 12-course tasting menu costs about $65 per person, the 130-seat restaurant was full on a recent Friday night. In less than three years, it has climbed into the ranks of Latin America’s top-rated restaurants.
“Thiago is seizing the idea that the future of cooking may rest more in the diversity of ingredients than in technical experimentation, and that the Amazon is uniquely endowed to go down this path,” said Carlos Alberto Dória, a sociologist who writes widely about Brazil’s food traditions.
Sometimes this quest for innovation involves forays into the Amazon rain forest surrounding Belém. On one such recent trip by boat on the Guamá River to the Ilha do Combu, a forested island of peach-palms where riverbank families eke out an existence collecting fruits like pupunha and açaí, Mr. Castanho waded through swarms of mosquitoes called carapanãs.
“A little bit of sacrifice is worth it,” said Izete dos Santos Costa, 49, a farmer on the island who grows organic cacao and sells it to Mr. Castanho. After he began making chocolate desserts from the cacao, her harvests became coveted by chefs in distant São Paulo.
With deforestation rising again and huge dams under construction in Brazil’s Amazon, Mr. Castanho views the growth of demand for foods from the rain forest as a potential shift providing a more sustainable way to develop parts of the vast region, starting with the organic cacao grown on the Ilha do Combu.
“Why should the Swiss be such giants in the world of chocolate when Switzerland doesn’t grow any cacao?” he asked. “We have all the ingredients we need in the Amazon to produce world-class cuisine,” he continued. “Maybe all that’s needed to take things to the next level is some imagination.”