A method of determining a sold-out state of a beverage dispenser is provided. The method includes providing a beverage dispenser including a pump having a gas exhaust port, a dispensing valve, and a sensor disposed on the pump gas exhaust port. The method may include activating the beverage dispenser to dispense a beverage through the dispensing valve and during the activating, sensing a gas exhaust pattern of the pump. The method may also include generating a signal based on the sensed gas exhaust pattern and determining whether the beverage dispenser is in a normal-pour state or a sold-out state. The method may also include providing feedback about the sold-out state to a user interface of the beverage dispenser.