Abstract: Proposed is a coffee machine for brewing coffee powder pre-packed in a cartridge. For perforating the cartridge, the bottom of the brewing chamber is provided with inclined perforator members which provide the cartridge with elongate slots that have a greater cross section than the cross section of the particular perforator member. A brewing chamber housing receives two chamber portions delimiting the brewing chamber. The upper chamber portion is adapted to vertically support the cartridge and biased by a spring. For closing the chamber, the brewing chamber housing is raised against a closure piston. The closure piston entering the brewing chamber moves the upper chamber portion against the force of the spring downwards towards the lower chamber portion. In the final position of the brewing chamber housing, the front portion of the cartridge is hydraulically sealed with regard to the rear portion of the chamber by sealing members.