I am certain of this because, when my mother wanted to please me, or when I was ill (often enough), she would order up 'yellow' rice, the commonest of all rices in the north of Italy and in Spain. The rice, sticky and hot; the butter, rich and melting; the saffron with its own sweet, high flavour: these are - when I want to look on the good side of things - the essence of my childhood; as are, when I want to remember the worst: cod-liver oil, rhubarb and soda, and fresh, still-warm ox blood (then a putative cure for tuberculosis).
Considering the fact that saffron is now the most expensive flavouring in the world, (about pounds 1 per gram for saffron of any quality), the fact that it is widely used in cooking (from Indonesia to the Middle East, in North Africa and in Spain and Italy) is nothing less than astonishing.
Historically, saffron was known to the Greeks, long cultivated by the Persians and in Kashmir, a significant item in Chinese herbal medicine, and apparently brought to Britain during the Crusades. It was especially cultivated near Hinton, Cambridgeshire, and in Saffron Walden, Essex.
For its true origins and history I await the promised book of Robert Johnson, who teaches Spanish and Latin American literature in New South Wales, Australia. The extract from his work, published in Petits Propos Culinaires 41 (Prospect Books, 45 Lamont Road, London SW10 0HU), promises a rich harvest.
Tradition has it that saffron is of Arab origin, because the word comes from the Arabic for yellow, za'faran. But as saffron is derived from a crocus (and the people who grow, harvest and dry it are called 'crokers'), it may well be, as some argue, that its true original home was the town of Cocyrus in south-east Asia Minor.
For much of ancient history, saffron seems to have been used primarily as a dye and a perfume, the colour being associated with nobility, the smell (potent) deodorising (or at least altering the smell of) orgies. It has also been used as a substitute for gold in illumination and to mark the spot on a Hindu pandit. Frankly, I think it is like many rare things: used primarily by the rich as a delicious prop to luxury. As it is the rich who make and enforce laws, there have always been stringent (and wise) laws against adulterating saffron. In the 16th century, three men were buried alive for such an offence.
The principal sources of saffron today are Spain, France, Sicily, Iran and Kashmir, though there are pockets growing elsewhere. You can tell good saffron by its colour, which is as deep and yellow-red as you can get outside of a Turner sunset. Any variation, towards light or dark, is to be avoided: this is either inferior saffron or saffron past its prime. It will, by the way, last a long time: traditionally in slightly damp leather bags, or in glass jars kept firmly away from light and heat.
Good cooks do not use ground, dried saffron. They use the filaments, which look like short strings but are actually the stigmas of the flower. Saffron is expensive because growing and harvesting the flowers is so labour-intensive and subject to such risks. The flowers have to be gathered in October, early in the morning, while they are opening. Each flower has three pistils and an experienced 'peeler' can do about 10,000 flowers in a day, producing between two and three ounces of the precious spice.
There are a few simple rules for the use of saffron, foremost among which is that it needs to be cooked for some five minutes in a warm liquid (milk is very effective) before it releases its full flavour. A second rule is that you do not need to use very much. Four to six threads of saffron will do a risotto milanese for four. A third is that heat and saffron go together, so do not try using it cold, unless all you want is the colour (and if that is all you want, cheat, like so many modern Persian or Indian dishes do, by using turmeric).
It is, of course, rice with which we mainly associate saffron, but that is far from its only use. It is, for instance, terrific with fish, especially the more highly flavoured fish. It is an essential ingredient of bouillabaisse and its cousin fish soups up and down the Mediterranean. And a baked mackerel that has been stuffed with saffron rice is a true delicacy.
As anyone who has eaten extensively in North Africa or the Near East will tell you, saffron also goes very well with lamb, and I myself am particularly partial to eggs baked en cocotte with saffron. Take a ramekin dish, fill the bottom with warm, but not browned, butter, in which you have allowed the saffron to open up, drop in the egg and put it in the oven.