These ingredients are simmered together with a cylindrical cloth bag filled with a mixture of eggs, milk, and buckwheat flour (known locally as "black wheat") for several hours.

The dish is presented with the cooked meats and vegetables and the farz is consumed with a sauce locally known as "lipig", made with melted butter, bacon, and shallots.

[6] It replaces wheat for food and becomes the basic cereal in Bas-Léon, "the part of Brittany where Breton is spoken, lives on buckwheat flour pancakes" wrote Stendhal.

[10] As early as 1732, Grégoire de Rostrenen, in his dictionary, defined the word fars as "farce cooked in a bag in the pot to eat with meat in the manner of Léon".

In all the houses of the country of Léon,[11] one found bags to make far (the production using finely sewn linen, the seams on the outside, were in the program of the domestic course of Saint-Pol-de-Léon, before marriage).

[12] In the middle of the 19th century, the vegetable boom in the agricultural economy, thanks to marine amendments, gave far en sac its current form.

The farz sac'h, cooked on its own or with bacon, is used to feed the agricultural workers, in particular the day laborers whom the peasant will hire every morning in the square of Saint-Pol-de-Léon and who are called plasennerien, those space.