Truffles are round, warty, and irregularly shaped They vary in size, being as small as a walnut to the size of a small grapefruit. They are found seasonally, mostly, between September and May.
The first mental image of truffles brings up images of the expensive French black truffle (Tuber melanosporum) from the Périgord region of southwest France, It is used to make pâté de foie gras, or the odorous white truffle (Tuber magnatum) of Alba, in the Piedmont district of Italy.
The early Greeks and Romans used these fungi in Europe as delicacies, aphrodisiacs, and medicines. They are among the most expensive of the world's natural foods.
Truffles are harvested in Europe with the aid of female pigs or truffle dogs, which are able to detect the strong smell of mature truffles underneath the surface of the ground. Some people dig for their truffles themselves when they see truffle flies hovering around the base of a tree. Once discovered, truffles can be collected in subsequent years at the same site.
The flavor of the truffle is directly related to its aroma. The chemicals necessary for the odor to develop are created only after the spores are mature enough for release, so they must be collected at the proper time or they will have little taste.
Truffles are also found in North Africa, the Middle East, and North America. On the desert after rainfall, knowledgeable Middle Eastern people collect the "black kame," Terfezia bouderi, and the "brown kame," Terfezia claveryi. They prefer the darker ones. In Texas, Tuber texensis is collected, and in Oregon, the white Tuber gibbosum.
Gaining in popularity and comparing favorably with the Italian truffle, the Oregon truffle is harvested in sufficient quantity to support commercial sales. James Beard claimed that the mature Oregon white truffle could be substituted for European varieties.
Because of their extremely high prices and their strong pungent taste, truffles are used sparingly, often only shaved or mixed with salt or herbs. Truffles can be found commercially as fresh produce or preserved.
White truffles are generally served raw, and shaved over steaming buttered pasta or salads. White or black paper-thin truffle slices may be inserted into meats, under the skins of roasted fowl, in foie gras, pâtés, or in stuffings. Some specialty cheeses contain truffles as well.
The flavour of black truffles is far less pungent and more refined than that of white truffles. It is reminiscent of fresh earth and mushrooms, and when fresh, their scent fills a room almost instantly.
While in the past chefs used to peel truffles, in modern times most restaurants brush the truffle carefully and shave it or dice it with the skin on so as to use most of this expensive ingredient.
Truffle oil is widely used as an economical way to infuse a dish with the aromatic qualities of the truffle, at a fraction of the cost of using fresh truffles.