The present invention relates to a closed cartridge (10), for extraction
under pressure, comprising a dish (12) with a bottom (13 ) with a central
part and a peripheral part and a side wall having substantially the shape
of a frustum of a cone and a circular edge with a diameter greater at the
bottom and a cover (15) welded to the periphery of the edge of the dish
and the cover is intended to be torn only through the effect of the force
of the extraction fluid when extraction starts, the cartridge comprising,
in the dish at the level of the bottom, a fabric (16) guaranteeing
retention of the solid substance when it is opened,in which the fabric
guaranteeing retention of solid substance is a sheet of fabric sealed in
the bottom of the dish in two zones, on the one hand in the central part
(17) and on the other hand in the peripheral part (18) of the bottom
(13).