A liquid dispenser device including an air flow channel for passing air from the outside towards the inside of a liquid reservoir; a closure member for closing the air flow channel, the closure member being referred to as an “air diffuser member” and being made out of a non-porous polymer material that is permeable to air; and an isolator casing for isolating the diffuser member, the isolator casing being configured in such a manner that the diffuser member is not in contact with the liquid from the reservoir, the casing including an air flow element for passing air towards the inside of the reservoir.