An infusion assembly, wherein a piston is positioned facing an open end of a cup, and is movable along a first axis to insert a container of powdered material into the cup; the container having been arrested, in use, by a gripper-type stop device in a position coaxial with the first axis and inside a through channel interposed between the piston and the cup; the gripper-type stop device being movable with and by the piston to perform a work movement towards the cup; and the cup having a second axis, and being mounted to oscillate, about a third axis perpendicular to the first axis, between a normal unloading position, in which the open end of the cup faces downwards, and a work position, in which the second axis is coaxial with the first axis.