Saffron is a commercial spice that comes from the bright red stigmas of the saffron flower, or Crocus sativus, which flowers in the fall in many different countries, including Greece, India, Iran and Spain. The Crocus sativus stigmas are the female part of the flower. During a good year, each saffron crocus plant might produce several flowers. Each saffron flower contains three stigmas, which are the only part of the saffron crocus that when dried properly, become commercial saffron. Each red stigma is like a little capsule that encloses the complex chemicals that make up saffron's aroma, flavor, and yellow dye. In order to release these chemicals, you must steep the saffron filaments or threads, which are actually the dried stigmas of the saffron flower. Powdered saffron is more efficient because it does not need to be steeped.
Since each saffron flower contains only three stigmas and the stigmas must be picked from each flower by hand. As such, more than 75,000 blossoms or 225,000 hand-picked stigmas of these saffron flowers are required to produce just about one pound of Saffron filaments, thereby making saffron the most precious and most expensive spice in the world.
Soil and weather conditions naturally vary in the saffron cultivating countries and so do the methods of drying the fresh saffron stigmas. The international measuring stick for determining the quality of saffron is called a photospectometry report, the result of a laboratory analysis of the three chemicals in the saffron stigma which relate to aroma, flavor and color. Even though saffron stigmas are red, their dye is the color of egg yolks which gives the appealing yellow to culinary dishes. The chemicals that are being analyzed in a photospectometry report are crocin (the source of saffron’s strong orange-yellow coloring property), picrocrocin (source of its flavor) and safranal (source of its aroma). The higher the saffron’s coloring strength, the higher its value, as the saffron's coloring strength determines its flavor and aroma. If saffron has the right coloring strength, it will have the right color and general appearance, whether it is in the thread or powder form.
The saffron powder, with a high coloring strength, offers many advantages over the threads. When saffron threads are ground into powder, the chemicals corresponding to aroma, flavor and color are immediately released. The powder is then stored carefully, away from moisture and light, just as the threads need to be in order to maintain their potency. When the saffron powder reaches the chef, it is ready to be added directly to any recipe. When the chef adds the saffron powder to a recipe, immediately the deep yellow dye, delicate aroma and unique flavor are released.
As for saffron in the thread form, in order to release the potent chemicals in the saffron threads, they must be inmersed in an alcoholic, acidic or hot liquid for longer than just a few minutes. This allows aroma, flavor and color to be generously extracted. Saffron threads can release aroma, flavor and color for 24 hours or more, depending on their quality.
N.B. According to Greek myth, handsome mortal Crocos fell deeply in love with the beautiful nymph Smilax. But his overtures were rebuffed by Smilax, and he was turned into a beautiful purple crocus flower.