Patent ID: 7856920

Claim:
Coffee maker for brewing coffee powder contained in a cartridge, comprising: a single brewing chamber adapted to receive said coffee powder cartridge; at least one means for punching said coffee powder cartridge; a pump for feeding hot brewing water through a single brewing water conduit into said brewing chamber, wherein said pump is operated with alternating current; means for restricting the amount of brewing water fed into said brewing chamber per unit of time to such an extent that the brewing water flows through said powder coffee cartridge received in said brewing chamber essentially unpressurized, said means for restricting including an adjustable throttle valve inserted into said brewing water conduit for varying the effective cross sectional flow area of said conduit, wherein said means for restricting the amount of brewing water fed into said brewing chamber per unit of time comprises means for restricting a flow rate of said pump, and wherein said means for restricting the flow rate of said pump comprises a phase controlled modulator, a wave packet controller or a controller for changing the frequency; and a control unit operationally connected to said pump and said means for restricting to selectively activate said pump and said means for restricting, in a first state to direct pressurized water into said brewing chamber sufficient for preparing an espresso beverage and in a second state to direct essentially unpressurized water into said brewing chamber sufficient for preparing a frothless beverage.