Abstract: This invention provides a method of ranking a characteristic of a liquid sample by providing a test container [11] having a viewing port [16] to liquid contained therein and through which electronic image data of a defined body of liquid sample [20] in the container can be captured. This data is compared with an electronic data model containing comparison data with which the captured electronic image data can be compared to provide a ranking. The image is captured and the image data is electronically compared with the comparison data to provide a characteristic ranking of the sample.