Abstract: In a system for preparing a beverage including a capsule including a flange-like rim and a sealing protrusion spaced from the lateral wall the capsule and extending outwardly of the flange rim, and a brewing device including a receptacle movable with respect to a receiving plate to provide a closed chamber for housing at least part of the capsule, the protrusion of the capsule includes at least one side, for example the internal side, that is inclined by an angle a within the range of 80 to 40 degrees with respect to the plane of the flange rim to have the protrusion contacting the external portion of the edge of the receptacle at least at one location selected from the top and the side of the protrusion.

Abstract: A capsule for preparing a beverage comprising a lateral wall (2), an inlet wall (3) and an outlet wall (4) forming a hollow body (5) where a brewing product is contained The inlet wall comprises a piercing area, wherein said area is pierced by a brewing device (20) comprising piercing means (21) extending along a predetermined path for perforating said capsule to inject a brewing liquid into the said capsule. The piercing area of the inlet wall (3) comprises at least one portion (10) protruding outside the said inlet wall (3), said portion (10) comprising an inner lateral wall (11), an outer lateral wall (12) and a perforating wall (13).