Beverage preparation device comprising a cylindrical chamber with a - jacket provided with a filling opening for receiving a powder-like or granular substance and an ejection opening for ejecting the substance, - a first and a second compression element (22; 23b, 32), positioned perpendicularly with respect to a longitudinal axis of the chamber, - a displacement member (2, 4, 5, 13) for relative displacement of the first compression element with respect to the jacket between a filling position, a compression position and an ejection position, wherein the compression elements (22; 23b, 32) in the filling position delimit a filling volume and the compression elements (22; 23b, 32) in the compression position delimit a preparation volume positioned along a longitudinal axis and at a distance from the filling volume, wherein the first compression element engages the inner wall of the jacket in a fluid-tight manner and - a fluid supply channel and a fluid discharge channel that in the compression position is in fluid-communication with the preparation volume, wherein - the second compression element (23b, 32) is fixedly connected to the jacket, and that an ejection member that is displaceable along a longitudinal axis with respect to the second compression element (23b, 32) is arranged in the chamber, which ejection member is fixedly connected to a shaft which enters through the second compression element (23b, 32) via a shaft seal arranged in the second compression element (23b, 32), wherein a fluid communication is present between the side of the ejection member turned towards the first compression element and the side facing towards the second compression element (23b, 32) of the ejection member, wherein the circumference of the ejection member is positioned at a certain distance from the inner wall of the product chamber in such a way that free fluid transport between the circumference of the ejection member and the inner wall of the product chamber is possible, - wherein in the compression position the ejection member is positioned close to or adjoins the second compression element (23b, 32) and - in the ejection position the ejection member is positioned at a distance from the second compression element (23b, 32), close to or outside of the ejection opening, wherein the fluid supply channel is arranged in the second compression element (23b,32), characterized in that the fluid supply channel discharges in the chamber via the compression surface of the second compression element (23b, 32) to allow flushing of the chamber via water supplied by the fluid supply channel in the ejection position, the water being allowed to leave the chamber past the ejection member. - jacket provided with a filling opening for receiving a powder-like or granular substance and an ejection opening for ejecting the substance, - a first and a second compression element (22; 23b, 32), positioned perpendicularly with respect to a longitudinal axis of the chamber, - a displacement member (2, 4, 5, 13) for relative displacement of the first compression element with respect to the jacket between a filling position, a compression position and an ejection position, wherein the compression elements (22; 23b, 32) in the filling position delimit a filling volume and the compression elements (22; 23b, 32) in the compression position delimit a preparation volume positioned along a longitudinal axis and at a distance from the filling volume, wherein the first compression element engages the inner wall of the jacket in a fluid-tight manner and - a fluid supply channel and a fluid discharge channel that in the compression position is in fluid-communication with the preparation volume, - the second compression element (23b, 32) is fixedly connected to the jacket, and that an ejection member that is displaceable along a longitudinal axis with respect to the second compression element (23b, 32) is arranged in the chamber, which ejection member is fixedly connected to a shaft which enters through the second compression element (23b, 32) via a shaft seal arranged in the second compression element (23b, 32), wherein a fluid communication is present between the side of the ejection member turned towards the first compression element and the side facing towards the second compression element (23b, 32) of the ejection member, wherein the circumference of the ejection member is positioned at a certain distance from the inner wall of the product chamber in such a way that free fluid transport between the circumference of the ejection member and the inner wall of the product chamber is possible, - wherein in the compression position the ejection member is positioned close to or adjoins the second compression element (23b, 32) and - in the ejection position the ejection member is positioned at a distance from the second compression element (23b, 32), close to or outside of the ejection opening,