Abstract: A liquid dispensing apparatus comprises a container having a peripheral sidewall, a bottom wall mounted at a lower end of the sidewall and a closure removably mounted to an upper end of the sidewall. A flexible tight plastic bag is mounted at an upper end thereof between the closure and the sidewall in order to hang in the container. The bag thus defines in the container a first and a second chamber which respectively contain the liquid to be dispensed and compressed air. A nozzle extends through the closure into the first chamber. A pressure regulating valve is mounted in the second chamber and defines therein an upper and a lower sub-chamber, with the bag being submitted to forces exerted by the compressed air contained in the upper sub-chamber. The pressure regulating valve ensures a constant pressure in the upper sub-chamber and thus on the bag, whereas the lower sub-chamber acts as a reservoir for the upper sub-chamber.