A cartridge containing one or more ingredients for the preparation of beverages. The cartridge comprises an inlet for the introduction of an aqueous medium into the cartridge, an outlet for a beverage produced from said one or more beverage ingredients, an aperture in a beverage flow path linking the inlet to the outlet which generates, in use, a jet of beverage, and an expansion chamber located downstream of the aperture. The expansion chamber comprises an expansion chamber inlet for receiving the jet of beverage and an expansion chamber outlet； and an air inlet located in the expansion chamber in the vicinity of the expansion chamber inlet. The cross-sectional area of the expansion chamber decreases in a downstream direction from the expansion chamber inlet to the expansion chamber outlet, and the cross-sectional area and profile of the expansion chamber outlet are substantially the same as the cross-sectional area and profile of the beverage stream as it passes through the outlet.
