A hand-written notice in the West London restaurant window advertised white truffle fresh from Italy. The lunch menu offered only two choices: truffle on pasta or truffle on risotto—both at substantial premiums to normal prices. I ordered the risotto, which arrived as a steaming bowl of very plain rice—no frills, no peas or bits of vegetable or meat. The head waiter hovered with a little plastic box and a stainless steel slicer. As he opened the lid, an earthy, musty, musky, garlic and cheesy smell drifted over the table. He shaved half a dozen extremely thin slivers of the brownish-white ball-shaped thing in the box onto the rice. It didn’t seem like much for the amount of money involved. But as the truffle slices were warmed by the steaming rice, the smell intensified and developed new notes—forest floor, damp leaves, sweaty socks and something indefinably sexy and alluring. After lunch—in fact, through the rest of the day and well into the evening—I experienced what aficionados call the “truffle burps”—little eructations of truffle flavour—the classic sign of a good truffle meal. Like the wild pigs of the French forest, the burrowing mammals of northern Italy or Australia’s long-nosed potoroo, I was hooked on truffles. Nearly twenty years later, I still am.

Truffles are smelly bags of spores, designed to be eaten. They are the fruiting bodies of fungi that grow in association with trees. They’re the underground equivalent of the mushrooms that pop up round trees in autumn, and the heady brew of chemicals that gives them their powerful aroma and beguiling flavour is their way of getting their spores distributed. Ordinary mushrooms push their caps above ground and shed spores onto the wind, but truffles rely on persuading animals to carry the spores around in their stomachs, to be dispersed around the forest in dung. As the fruit bodies grow and ripen, they synthesise aroma chemicals which spread out into the soil and eventually reach the air. Long before a passing human nose would detect anything, animals and insects will track them down and start feasting. These are not subtle scents. They have considerable complexity and delicacy, but underlying that is power. If you put your nose into the hole where a perfectly ripe truffle has just been unearthed, the smell can be overpowering—almost sickening. If you leave a ripe truffle in the fridge overnight, its smell will permeate everything in there. To a pig, or to the sensitive nose of a trained dog, finding truffles is not much of a challenge.

That smell is the key to the high value humans put on truffles. It is attractive in itself—we’re mammals, after all, and truffles have evolved to be attractive to our sort—but truffles also have a transformative effect on food. The Périgord or French black truffle, Tuber melanosporum, not only lends its own flavour to the dishes in which it appears, but also seems to intensify the flavours of the ingredients it accompanies. A steak with a truffle sauce is more meaty, a simple egg becomes a luxury item. That’s why the black truffle is one of the key ingredients in the finest expressions of French cuisine, as highly valued as fine wines or foie gras, and that’s why fresh truffles can command high prices. New Zealand grown Périgord black truffle sells for around $3500 per kilo during our winter season—June to August—and we can’t grow enough to meet domestic demand, let alone begin exporting to the world.