The present invention relates to a brewing head of an espresso maker. The brewing head includes a pressure sealed brewing chamber, and a movable lifting piston forming a floor of the brewing chamber. The movable lifting piston has apertures therethrough. A fill opening is in communication with the brewing chamber for supplying the brewing chamber with fresh ground espresso. A water inlet is provided for feeding hot water through the apertures and into the brewing chamber. The movable lifting piston lifts a cake of used ground espresso located thereon up to an upper edge of the brewing chamber after brewing the espresso. A clearing element laterally pushes the cake off from the lifting piston after the cake is moved to the upper edge of the brewing chamber by the lifting piston, so as to clear the brewing chamber of used ground espresso.
Such an espresso maker is described by European Patent No. 0 443 054. In this known espresso maker, the water supply and the clearing blade are arranged on a carriage which is linearly displaceable above the brewing chamber. The brewing process of this device occurs at a pressure of approximately 12 bar.
A cake of leached espresso grounds is lifted by the lifting piston, and laterally transported off the lifting piston, by a semicircular-shaped clearing element disposed on the aforementioned carriage.
The inlet for the hot water is configured as a flexible hose, which represents a source of danger because of the very high pressure involved.
This known espresso maker has several drawbacks. For example, during the brewing process, the brewing chamber and the carriage must be sealed from each other. Seals are used which are located in a region of a sliding plane between the brewing chamber and carriage, and are therefore subjected to heavy wear. Further, the linear, reciprocating movement of the carriage also requires a very complicated mechanical control system and a flexible water supply (i.e., a flexible hose). Moreover, the water supply is also under a pressure of 12 bar, and therefore represents a source of danger.