BEVERAGE MACHINE WITH ADJUSTABLE SEALING DEVICE

A machine (1) for serving a beverage (7) via a dispensing outlet (8) to a consumer receptacle (9) by mixing water (3) from a water source (3) with a flavouring ingredient (2), has a mixing unit (10) that comprises: a stationary support (11); a seat (12) having an ingredient opening (120); a closure part (13) configured to close and open the ingredient opening (120); and a wall part (14) that is movable inside the seat (12). The seat (12), the closure part (13) and the wall part (14) are: mounted to the support (11); and relatively movable between a transfer configuration and a mixing chamber configuration in which the seat (12) and the closure part (13) and the wall part (14) form a mixing chamber (12′) fluidically connected with the water source (3) The closure part (13) comprises a closure holder (131) and a peripheral sealing member (130) displaceably mounted on the holder (131) and urged away from the holder (131) against the seat (12) while the flavouring ingredient (2) is mixed with the water (3) in the mixing chamber (12′).