Saffron agents. It must, therefore, be stored away in air-tight containers to minimise contact with atmospheric oxygen. Saffron is somewhat more resistant to heat. Saffron is not all of the same quality and strength. Strength is related to several factors including the amount of style picked along with the red stigma. Age of the saffron is also a factor. More style included means the saffron is less strong gram for gram, because the colour and flavour are concentrated in the red stigmas. Saffron from Iran, Spain and Kashmir is classified into various grades according to the relative amounts of red stigma
Trade and use of saffron France, Israel, Mexico, New Zealand, Turkey (especially Safranbolu), California, and Central Africa. The high cost of saffron is due to the difficulty of manually extracting large numbers of minute stigmas, which are the only part of the crocus with the desired aroma and flavour. An exorbitant number of flowers need to be processed in order to yield marketable amounts of saffron. Obtaining of dry saffron requires the harvesting of some 50,000 flowers, the equivalent of an association football pitch's area of cultivation, or roughly . By another estimate some 75,000 flowers are needed to produce one pound of dry saffron.