The invention provides devices and methods for acoustically determining the properties of the contents of one or more reservoirs in a plurality of reservoirs. Each reservoir is adapted to contain a fluid. An acoustic radiation generator can be positioned in acoustic coupling relationship to each of the reservoirs. Acoustic radiation generated by the acoustic radiation generator is transmitted through each reservoir to an analyzer. The analyzer is capable of analyzing a characteristic of the transmitted acoustic radiation and optionally correlating the characteristic to a property of the reservoirs' contents. Properties that may be determined include volume, temperature, and composition. The invention is particularly suited to determining the properties of the contents of a plurality of reservoirs to allow for accuracy and control over the dispensing of fluids therefrom.