Abstract: A delivery assembly for a coffee beverage extracted under pressure by means of water through a substrate of powdered coffee comprises an extractor body (11) which has a passage circuit (13) from an entry aperture (24) for the water to a delivery aperture (25) of the coffee beverage, there being present, along the passage circuit (13), a first seating (16) that acts as an extraction chamber to receive the substrate of powdered coffee made downstream of the entry aperture (24) and, downstream of the first seating (16), a second seating (17) communicating with the delivery aperture (25) and the delivery assembly also comprises a proportional membrane valve (15) selectively adjustable to control the delivery flow of the coffee beverage at exit from the first seating (16) and able to be housed in the second seating (17).