A beverage preparation machine of the type which uses pre-packaged containers of beverage ingredients comprises a cartridge recognition device for determining the type of beverage to be prepared from a cartridge inserted into the machine and a variable geometry valve located downstream of a cartridge when inserted in the machine. The valve enables preparation of beverages at a range of pressures by having at least an open position and at least one restricted flow position, and a controller for selecting an initial valve position and controlling the subsequent operation of the valve according to the determination of the type of beverage to be prepared by the cartridge recognition device.