In 19th-century Rio de Janeiro, hygiene concerns made the use of human hands a major problem. As early as 1884, the French baker Delmilhac advertised his bakery as an example of technical advancement: mechanical kneader, special oven, and "less human contact with the dough."

Rafa Brito Pereira (@theslowbaker) has always managed to attract consumers seeking quality to unlikely places. His Slow Bakery (@theslowbakery), now in a less unusual location, continues to make the best bread in Rio for 10 years, and still attracts a crowd that arrives with luggage straight...