Patent ID: 8671829

Claim:
A brewing device comprising a brewing cylinder and a piston, the piston being received in and reciprocally movable inside the brewing cylinder, the brewing device being connected to a water supply device that supplies a liquid to the brewing cylinder, wherein the piston comprises a piston head and a piston rod, the piston head being of a hollow form and comprising a bar mounted to an inside wall of the piston head, the piston rod forming a pivot hole that is rotatably jointed to the bar in such a way to allow the bar to translate with the piston head, the piston rod forming a lid at a location close to the pivot hole that selectively sets the piston in a closed condition, whereby through change of position of the lid relative to the piston head by the movement of the bar, a hole at a bottom of the piston head is opened or closed and the piston is switchably set in an open configuration or a closed configuration for readily controlling amount of water contained in the brewing cylinder to meet various conditions for quantity of brewing water.