The story behind one of the world’s most revered ingredients

Lumpy though it may be, unattractive, covered in dirt, the truffle commands a reverence shared by few edible objects.

Nature has designed the truffle for exclusivity, the kind that justifies a price tag of up to $1,000 per pound. It’s basically a mushroom, but a mutant one. A little fungi biology here: Truffles have internal spores. This means they can’t reproduce the way other mushrooms do, by sending their spores out on the wind. A truffle must be eaten by an animal, usually a rodent, which then moves off and spreads the spores when it, you know, “un-eats.”

They grow deep underground, developing a heavy aroma that peaks when they’re fully mature. This scent attracts the animals, and also makes truffles deeply flavorful and beloved of gourmands.

Add to this the fact that it takes at least six years for truffles to reach maturity, and that they’re hard to find in their underground nests, and that they must be eaten within days of harvest – you can see how they gained their aura.

The ultimate truffles are the Perigord, or French black truffle, and Piedmont, or Italian white. These are the ones that command top dollar. The Perigord grows wild in oak forests of the Perigord region of France, although it has been cultivated elsewhere, including the United States. The Piedmont is found in parts of Italy and Yugoslavia.

In Europe, truffles are hunted by lady pigs, drawn to a scent that resembles that of a gentleman pig’s hormones. Dogs also have been trained to pick up this scent and have somewhat of an advantage among hunters, as they don’t try to eat the truffles once they find them.

More fungi biology: The truffle’s attractive scent emanates only when it is mature and at the height of its flavor, which means the animals are only digging out the best. In the United States, pigs and dogs haven’t reached this level of expertise, so most truffle hunting is done by humans using rakes to comb the earth. Having lesser olfactory talent, humans hunt by eyeball and can’t discern between a ripe truffle and one that’s less so, meaning that many North American species aren’t considered as tasty.

Truffle types are many, including Oregon species in black, brown and white. There’s also a Texas truffle and many types of Chinese truffles. Commercial truffle-growing is a new industry just starting up in parts of the United States, particularly the South, where the climate is right.

Being so expensive and so flavorful, truffles are used sparingly in cooking. They’re usually shaved and a tiny bit might be sprinkled into almost any cooked dish – even scrambled eggs – to give it that distinctly musky truffle essence. A classic use is in paté.

Because they are so rare and perishable, finding a fresh truffle is a treasure hunt. A few Web sites offer them by mail order, but great care must be taken to be sure you’re not spending a lot on poor quality.

Truffle oil is the home cook’s best alternative. Oils can be used in small amounts in many of the same ways as fresh truffles. European oils in many grades of quality may be found in gourmet food shops and even some supermarkets. For a made-in-America oil, visit www.oregontruffleoil.com, which sells a $35, 5-ounce bottle made from Oregon white truffles.