Coloring Strength

The coloring strength of saffron determines how strong the flavour and aroma are for a particular yield of saffron crop. Coloring strengths differs depending on the climate and soil conditions that the saffron is cultivated in. Ideally saffron thrives in dry, semi-arid climates that get a deluge of rain at the beginning of the gestation cycle.

Saffron coloring strength is graded by the international organization for standardization (ISO) and by the federal government of Spain in two separate but very similar manners.

ISO

A higher rating number on the ISO saffron grading system denotes higher quality saffron. The number is calculated by measuring how much light the saffron stigma absorbs or its light absorbance rate. The logarithmic formula is as follows A? = - log(I / I0). The ISO then grades saffron stigmas in four groupings 1, 2, 3 and 4. Below a chart for further explanation -

ISO Grading	Light Absorbance Rate

1	190
2	150-19
3	110-150
4	80-110

The federal government of Spain has a similar grading system based upon the ISO light absorbance rate and it is illstrated below -

Grade	ISO Score

Coupe	> 190
La Mancha	180-190
Rio	150-180
Standard	145-150
Sierra	< 110

SaffronChef.com only sells the highest quality ISO grade 1 saffron.