Four Barrel Coffee is an independent, locally owned roastery in San Francisco that sources almost all of its coffee directly from third generation farmers and mill workers in Latin America, Indonesia, and East Africa. Roasting takes place on a vintage 1957 German machine, and the process is entirely manual, relying on highly trained people rather than computers to control heat and airflow. The roasting style is focused on cleanness, sweetness, acidity, and complexity. Four Barrel operates a pair of cafes in San Francisco and holds a partnership stake in The Mill.