Abstract: A system for preparing an amount of predetermined beverage starting from an extractable product. The system includes (a) an interchangeable capsule; and (b) a percolating machine for preparing infusions. A dispensing device of the percolating machine includes several perforation tips of the bottom intended to perforate the inlet area of a traditional capsule to create an inlet opening for the fluid. The system is characterized in that the inlet area includes a plurality of valves, and in that the perforating tips are in contact with the inlet area without performing any perforating action thereon.