Saffron comes from the stigmas of the Crocus sativus flower and is grown in regions with a Mediterranean climate, such as Iran, Spain, India, and Greece. It is renowned for its unmistakable aroma, subtle earthy flavor, and the rich golden-yellow color it lends to dishes. Because it is harvested by hand, saffron is the most expensive spice in the world. Usually, it is sold in small quantities, and it should be used sparingly—too much saffron will give food a medicinal taste. Store any leftover saffron for up to 6 months wrapped in foil and placed in an airtight container in a cool, dark place.