The present invention discloses a self-venting package (6) for packing a food preparation and warming it up comprising: at least one flexible film forming a first wall comprising a sealant layer (9) and a support layer (10), said flexible film being sealed by a peripheral seal (4) onto a second wall or on itself, thereby forming a main enclosure confining the food preparation; a rupturable seal (3) isolating a venting hole (1) from said main enclosure, said rupturable seal being arranged for opening, in use, a path to the venting hole upon internal pressure increase in said main enclosure, caracterised in that a specific region (5) of the rupturable seal is weakened by means of a welded area with a reduced sealant lay er thickness, said welded area guiding, in use, the rupture of said rupturable seal to the venting hole.