An apparatus for extracting a substance contained in a sachet for preparation of a beverage has a first member having raised and hollow portions for forming a flow zone and a second member for cooperating with the first member to form a chamber to contain the sachet for extraction of the substance and to grip the edge of the sachet to ensure fluid-tightness upon being tightened, each member being configured for forming substantially half of the chamber for containing and ensuring a specific sachet shape. In one embodiment, the second member has provision for perforating an upper surface of a sachet for introducing water into the sachet. In another embodiment, the first member has an injector member which projects beyond the raised portions for perforating and introducing water into the sachet. The first and second members may be mounted on a chassis so that the members are mounted about an axis so that upon movement about the axis, the members are brought together so that they form the chamber, and a rim of the first member and an edge of the second member cooperate for gripping an edge of a sachet.