Kesar is one of the most expensive Indian spices as well. The reason being that extracting the stigmas from the flower calls for intense labor work and also, it needs fifty to seventy thousand flowers to produce just one pound of usable saffron. The people involved in the production and harvesting of saffron have to be very particular about its timely extraction as the flowers wilt very easily and the extraction have to be done well before their wilting.
The quality of saffron is graded as per the laboratory measurements. The uniform set of standards for grading kesar as prescribed by the International Standards Organization is ISO 3632. technically, the grade actually defines the attributes of picrocrocin (flavor), safranal (fragrance) and crocin (color) content in saffron stigmas. Visually, the more deep the color is, the more strong the fragrance would be and the fuller would be its flavor.
The grades for this spice range from category IV (less than 80) upto category I (190 or greater than that). The finest of all kesar has 250 degrees of color strength and the prices are thus, set as per the ISO grading given to it. While buying saffron, make sure you go for deep maroon colored stigmas with little or no light colored strands. A dull red shade is a sign of age which should indeed be avoided.
Saffron has a very distinct taste and smell thus, while using it one has to be very careful. Just a couple of strands can do the job fine though be cautious, as too much of kesar can render the dish bitter. Apart from the flavor, the yellow-orange color that it provides to the food makes the simplest of recipe look spectacular. This spice teams up well with ginger, cinnamon, tomatoes and cardamom. Use it for seasoning or garnishing but just be sure of the amount you use for, a spoiled curry is definitely not what you be looking forward to.
Find detailed information about the same at Kesar