Filling a reservoir that size is not a neutral act. Farms went under. River towns that had grown along the floodplain found their best bottomland at the bottom of a lake, and families who had worked those fields for generations had to decide what to do with land that ended at a shoreline. What came back was different money: boats, fishing, weekend visitors, hotels. By 2006 Alfenas counted eighteen hotels with roughly 1,200 rooms, most of them serving people who had driven in from Belo Horizonte or São Paulo to spend a weekend on the water. Historians who have interviewed residents about the lake find a complicated inheritance — pride in the scale of it, and a persistent memory of what the water covered. Both things are true at once, and the town's slogan only mentions one of them.

Before the lake and after it, Alfenas is a coffee city. Sixteen thousand hectares of the municipality are planted with it, on the hills of southern Minas that produce some of the most sought-after arabica in the world, and the Brazil Specialty Coffee Association keeps its headquarters here — a small detail that says a great deal about where this town sits in the global chain between a plantation and a flat white in another hemisphere. Corn follows at six thousand hectares, then potatoes, beans, tomatoes, vegetables, bananas, citrus. The 2006 agricultural census counted 1,102 farms across 56,821 hectares, worked by more than seven thousand people, of whom fewer than three thousand were related to the farm owner. The elevation helps: at 888 metres, with cool nights, the cherries ripen slowly and the beans develop the acidity buyers pay for.

The name arrived by a long route. Members of the Martins Alfena family were among the first settlers on this ground, and they carried a surname taken from Alfena, a town in northern Portugal. That Portuguese place name is itself Arabic — al-hinna, henna, the dye plant — left behind by the centuries when the Iberian peninsula was under Moorish rule. So a word for a reddish dye, spoken in Arabic in medieval Portugal, ended up naming a coffee city in the Brazilian highlands. For a while the settlement was Vila Formosa de Alfenas; the name was shortened in 1871 to stop it being confused with a municipality of the same name over in Goiás. The municipality had been emancipated in 1860 and became a city in 1869.

Alfenas is a college town, which is unusual for a place of this size and explains a good deal about it. UNIFAL began in 1914 as a school of pharmacy and dentistry, spent most of the twentieth century as a specialist institution, and became a full federal university in 2005; enrolment passed five thousand students by 2013 across more than thirty undergraduate programmes. Unifenas, the private university named for José do Rosário Velano, adds several thousand more, with strengths in agronomy, veterinary and animal science. Between them they give a municipality of about 79,000 people a permanently young population, a medical and dental infrastructure well beyond its weight class — four hospitals with 477 beds, twenty-five health clinics — and a human development index that ranks eighth among the 853 municipalities of Minas Gerais. Students, coffee, and a lake: it is a reasonable formula for a small city, and Alfenas has been running it for sixty years.