A cartridge attachable to a cup for controlled brewing of loose-leaf tea in the cup when the cartridge is provided on a top rim of the cup, the cartridge comprising: a top, lid-shaped portion for covering the cup; an infusion chamber for containing loose tea leaves and infusing a liquid with substances from the tea leaves to brew tea; a chamber wall extending from the lid-shaped portion and enclosing the infusion chamber, which chamber wall is impervious to the liquid and defines the infusion chamber, the chamber wall having a liquid tight inner surface facing the infusion chamber, which defines the inside of the infusion chamber, and an outer surface facing away from the infusion chamber towards the exterior; a passage in the chamber wall between the infusion chamber and an exterior thereof, the passage comprises an opening in the chamber wall between the inner surface and the outer surface and the passage having: an open state in which the infusion chamber is in liquid communication with the exterior, to transport the substances from liquid in the infusion chamber into liquid in the exterior during brewing tea, and a closed state in which the liquid inside the infusion chamber is closed off from the liquid in the exterior to stop a concentration of the substances in the liquid in the exterior from increasing; and a manual control manually controllable by a human-being for bringing the passage from the open state into the closed state; characterized in that the cartridge comprises an outer wall covering at least a part of the outer surface of the chamber wall, with covered parts of the outer surface, in that where the outer wall covers the outer surface of the chamber wall, said covered parts of the outer surface are separated from the exterior by the outer wall, which outer wall is movable relative to the chamber wall to cover and close the opening in the chamber wall; in that the chamber wall is shaped as a container for the loose tea leaves, the outer wall is shaped as a receptacle which holds the container, the container being movable relative to the receptacle to bring the passage into the open state or the closed state, and the top, lid-shaped portion has an annular shape attached to the outer wall with an axial opening through which the chamber wall is inserted; and in that the manual control engages on the chamber wall or the outer wall to move the chamber wall relative to the outer wall. a top, lid-shaped portion for covering the cup; an infusion chamber for containing loose tea leaves and infusing a liquid with substances from the tea leaves to brew tea; a chamber wall extending from the lid-shaped portion and enclosing the infusion chamber, which chamber wall is impervious to the liquid and defines the infusion chamber, the chamber wall having a liquid tight inner surface facing the infusion chamber, which defines the inside of the infusion chamber, and an outer surface facing away from the infusion chamber towards the exterior; a passage in the chamber wall between the infusion chamber and an exterior thereof, the passage comprises an opening in the chamber wall between the inner surface and the outer surface and the passage having: an open state in which the infusion chamber is in liquid communication with the exterior, to transport the substances from liquid in the infusion chamber into liquid in the exterior during brewing tea, and a closed state in which the liquid inside the infusion chamber is closed off from the liquid in the exterior to stop a concentration of the substances in the liquid in the exterior from increasing; and an open state in which the infusion chamber is in liquid communication with the exterior, to transport the substances from liquid in the infusion chamber into liquid in the exterior during brewing tea, and a closed state in which the liquid inside the infusion chamber is closed off from the liquid in the exterior to stop a concentration of the substances in the liquid in the exterior from increasing; and a manual control manually controllable by a human-being for bringing the passage from the open state into the closed state; characterized in that the cartridge comprises an outer wall covering at least a part of the outer surface of the chamber wall, with covered parts of the outer surface, in that where the outer wall covers the outer surface of the chamber wall, said covered parts of the outer surface are separated from the exterior by the outer wall, which outer wall is movable relative to the chamber wall to cover and close the opening in the chamber wall; in that the chamber wall is shaped as a container for the loose tea leaves, the outer wall is shaped as a receptacle which holds the container, the container being movable relative to the receptacle to bring the passage into the open state or the closed state, and the top, lid-shaped portion has an annular shape attached to the outer wall with an axial opening through which the chamber wall is inserted; and in that the manual control engages on the chamber wall or the outer wall to move the chamber wall relative to the outer wall.