The ColorFlex EZ Citrus measures Citrus Number, Citrus Redness and Citrus Yellowness. These indices were primarily intended to score orange juice concentrate, but in practice have also been used for grapefruit and lemon juices. In addition to the citrus values, the instrument can also measure in terms of the Hunter Lab scale as well as other widely used color scales. Thus the system can also be used to measure the reflected color of virtually any opaque or semi-opaque liquid.