 His paternal grandfather Miguel Bau Isern (1836-1911) ran a chocolate manufacture in Tortosa and served as mayor of the city in 1901-1903, co-founding Banc de Tortosa, Cambra Agricola de Tortosa and the local Cambra de Comerç.One of his 16 children and Joaquin's father, José Bau Vergés (1868-1935), was an oil and vinegar trader and producer.He grew from a local merchant, transporting oil on his mules, to "el rei de l'oli", the owner of Aceites Bau S.A., a Tortosa-based company operating two factories, selling on the national Spanish market and exporting to South America, especially to Argentina.