Don’t be seduced by fake truffle oil this Christmas

Truffles smell of sex. Even if we can’t quite say what we mean by ‘smell’ or ‘sex’ in this sentence, the much sought-after underground fungi emit something analogous to the pheromones that subconsciously attract us to other human beings. On the conscious level, these members of the family Tuberaceae release aromas ranging from floral to garlic to petrol to old socks, which pigs and dogs also find appealing. It can be faked, too. Most so-called truffle oil gets its scent from the chemical 2,4-Dithiapentane.

In Truffle Hound, his pacy travelogue-cum-foodie manual, Rowan Jacobsen deals with about a dozen species of truffles (or other near-truffle fungi). In practice, there are only two that command our attention: the Italian white Alba truffle, Tuber magnatum, and the one Jacobsen calls the black winter truffle, Tuber melanosporum, often called the Périgord truffle. The more prized white truffle fetches mighty prices and is used parsimoniously, by shaving it over cooked food with a dedicated utensil. Its outrageous fragrance and slight crunch are its USP. It’s never cooked, but its whiff is enhanced by the warmth of the pasta or egg over which it is shaved. The more common, but still rare, black winter truffle is sometimes cooked in foie gras, inserted under the skin of a chicken, or baked whole in a pastry covering. I can testify that it is the supreme hang-over cure. Once, in Lyon, where my wife and I had had one too many three-star meals, a sympa chef served us only a glass of champagne, a whole raw black truffle, a sharp knife and a salt cellar.

The folklore associated with truffles — that they are created by lightning, so thunderstorms in August and September augur well for the autumn; that they always appear in exactly the same spot, growing on or between the roots of oak or hazelnut trees, at exactly the same day every year in the lunar calendar — serves a purpose: to disguise the fact, writes Jacobsen, that ‘95 per cent of the world’s black winter truffle crop is farmed’.