A cartridge containing one or more beverage ingredients and being formed from substantially air- and water-impermeable materials. The cartridge comprises an inlet for the introduction of an aqueous medium into the cartridge, and an outlet for a beverage produced from the one or more beverage ingredients. The cartridge comprises means for producing a jet of the beverage having an aperture in a beverage flow path linking the inlet to the outlet, and one or more microscopic projections at or in the vicinity of the aperture for contacting the beverage flow path.