In fact, saffron sample grading depends on laboratory standards set for color, flavor and aroma, which means testing the major components crocin, picrocrocin and safranal through photospectroscopy. They must surpass a given ceiling in order to be considered even at the lowest or poorest category. Crocin, in particular, is the primary consideration because all other components are affected by its presence. Authentic saffron threads and powders are graded from I to IV, with I as the finest and IV the poorest. The following is the grading scale for crocin absorbance:
1. Grade I: >190
2. Grade II: >150
3. Grade III: >110
4. Grade IV: < 110