Abstract: A packing carton for packing pouch-type beverage containers stands on two sides, referred to as bottom surfaces, while in the open state and comprises halves which are open at their respective tops. Each bottom surface is delimited on four sides by carton sides, and the halves have a common longitudinal side, which is bent in the middle when in the open state, and comprises stiffening flaps on the transverse sides. The stiffening flaps are extensions on the transverse sides. A machine for closing such a packing carton is also disclosed, as well as a related method for closing the packing carton.