A system, method and apparatus for detecting the level of acidity or pH of material in a beverage container. The system includes a sensor assembly including a pH sensor. Preferably, a controller is provided and receives a signal from the sensor assembly for controllably operating functions of the beverage container or dispenser based on the detection signal from the sensor assembly relating to material in the container. The controller may prevent further dispensing or may indicate a level of freshness based on baseline pH values or a range of values for the particular beverage contained.