Capsule containing a substance for the preparation of a potable beverage by extracting and/or dissolving the substance by means of supplying a fluid under pressure into the capsule, wherein the capsule comprises an aluminum capsule body having a central capsule body axis, said aluminum capsule body being provided with a bottom, a side wall and an outwardly extending flange, the capsule further comprising an aluminum cover attached to the outwardly extending flange, the cover hermetically closing the capsule, wherein the capsule further comprises a sealing member at the outwardly extending flange for providing a fluid sealing contact with an enclosing member of a beverage preparation device if the capsule is positioned in the enclosing member of the beverage preparation device and the enclosing member is closed by means of a closing member of the beverage preparation device, such as an extraction plate of the beverage preparation device, such that the outwardly extending flange of the capsule and at least a portion of the sealing member of the capsule are sealingly engaged between the enclosing member and the closing member of the beverage preparation device, wherein the enclosing member of the beverage preparation device comprises an annular element having a central annular element axis and a free contact end, said free contact end of the annular element optionally being provided with a plurality of radially extending open grooves, characterized in that, the sealing member forms a bearing for the enclosing member of the beverage preparation device if the capsule is positioned in the enclosing member of the beverage preparation device and the enclosing member is closed by means of a closing member of the beverage preparation device, said bearing enclosing at least a portion of the free contact end of the annular element, wherein prior to use at least a first portion of the bearing lays at a first height above the cover, wherein, in use, upon closing of the enclosing member by means of the closing member the at least one first portion of the bearing is lowered by means of the free contact end of the annular element being moved towards the closing member wherein the bearing is at least partly folded over the free contact end of the annular element so that after closing of the enclosing member by means of the closing member the at least one first portion of the bearing lays at a second height above the cover wherein the first height is larger than the second height and the second height may be zero, wherein the sealing member comprises two spaced projections (50, 51), each projecting from the outwardly extending flange and a plateau between the two projections (50, 51) so that at least a first portion of the plateau defines a predetermined depth of a space between the two projections (50, 51), wherein the radial distance between the two projections (50, 51) is such that the free contact end of the annular element is enclosed by the two projections (50, 51) if the capsule is positioned in the enclosing member of the beverage preparation device and the enclosing member is closed by means of a closing member of the beverage preparation device and wherein prior to use the at least one first portion of the plateau lays at a first height above the cover so that the space has a first depth wherein, in use, upon closing of the enclosing member by means of the closing member the at least one first portion of the plateau is lowered by means of the free contact end of the annular element being moved towards the closing member so that the plateau is at least partly folded over the free contact end wherein after closing of the enclosing member by means of the closing member, the at least one first portion of the plateau lays at a second height above the cover wherein the first height is larger than the second height and the second height may be zero and the space has a second depth which is larger than the first depth, and wherein the sealing structure and the remainder of the capsule body are made of the same plate material.