A truffle is the fruiting body of a subterranean Ascomycete fungus, predominantly one of the many species of the genus Tuber. Some of the truffle species are highly prized as a food. French gourmand Jean Anthelme Brillat-Savarin called truffles “the diamond of the kitchen”. Edible truffles are held in high esteem in Middle Eastern, French, Spanish, Italian, Greek and Georgian cooking, as well as in international haute cuisine. Truffles are ectomycorrhizal fungi and are therefore usually found in close association with the roots of trees.
Looking for truffles in open ground is almost always carried out with specially trained pigs (truffle hogs) or, more recently, dogs. The Lagotto Romagnolo is currently the only dog breed recognized for sniffing out truffles(although virtually any breed could be trained for this purpose). The female pig’s natural truffle-seeking, as well as her usual intent to eat the truffle, is due to a compound within the truffle similar to androstenol, the sex pheromone of boar saliva, to which the sow is keenly attracted. In Italy, the use of the pig to hunt truffles is prohibited since 1985 due to damage caused by animals to truffle’s mycelia during the digging that dropped the production rate of the area for some years.
White truffle – The “white truffle” or “trifola d’Alba” (Tuber magnatum) comes from the Langhe and Montferrat areas of the Piedmont region in northern Italy and, most famously, in the countryside around the cities of Alba and Asti; in Italy it can also be found in Molise, Abruzzo, and in the hills around San Miniato, in Tuscany. It is also found on the Istria peninsula, in Croatia in the Motovun forest along the Mirna river, and in Slovenia along the Dragonja and Rizana river, as well as in the Drome area in France. Growing symbiotically with oak, hazel, poplar and beech and fruiting in autumn, they can reach 12 cm (5 in) diameter and 500 g, though are usually much smaller. The flesh is pale cream or brown with white marbling. Italian white truffles are very highly esteemed and are the most valuable on the market: The white truffle market in Alba is busiest in the months of October and November when the Fiera del Tartufo takes place. In 2001, the Tuber magnatum truffles sold for between $1000–$2200 per pound ($2000–$4500 per kg); as of December 2009 they were being sold at $14,203.50 per kilogram. The record price paid for a single white truffle was set in December 2007, when Macau casino owner Stanley Ho paid $330,000 (£165,000) for a specimen weighing 1.5 kilograms (3.3 lb), discovered by Luciano Savini and his dog Rocco. One of the largest truffles found in decades, it was unearthed near Pisa, Italy and sold at an auction held simultaneously in Macau, Hong Kong and Florence. This record was then matched on November 27, 2010 when Ho again paid $330,000 for a pair of white truffles, including one weighing nearly a kilogram. The Tuber magnatum pico white truffle is found mostly in northern and central Italy, while the Tuber borchii, or whitish truffle, is found in Tuscany, Abruzzo, Romagna, Umbria, the Marche and Molise. Neither of these is as aromatic as those from Piedmont, although those from Città di Castello come quite close.
Black truffle – The black truffle or black Périgord truffle (Tuber melanosporum), the second-most commercially valuable species, is named after the Périgord region in France and grows with oak and hazelnut trees. Black truffles are harvested in late autumn and winter. The genome sequence of the black truffle was published in March 2010. The black summer truffle (Tuber aestivum) is found across Europe and is prized for its culinary value. Burgundy truffles (Tuber uncinatum) are harvested in autumn until December and have aromatic flesh of a darker colour.
A less common truffle is “garlic truffle” (Tuber macrosporum). In the U.S. Pacific Northwest, several species of truffle are harvested both recreationally and commercially, most notably, the “Oregon white truffles”, Tuber oregonense and Tuber gibbosum. The “pecan truffle” (Tuber lyonii) is found in the Southern United States, usually associated with pecan trees. Chefs who have experimented with them agree “they are very good and have potential as a food commodity”. Although pecan farmers used to find them along with pecans and discard them, considering them a nuisance, they sell for about $100 a pound and have been used in some gourmet restaurants.
Because of their high price and their pungent taste, truffles are used sparingly. Supplies can be found commercially as unadulterated fresh produce or preserved, typically in a light brine. White truffles are generally served raw, and shaved over steaming buttered pasta or salads or fried eggs. White or black paper-thin truffle slices may be inserted into meats, under the skins of roasted fowl, in foie gras preparations, in pâtés, or in stuffings. Some speciality cheeses contain truffles, as well. The flavor of black truffles is far less pungent and more refined than that of white truffles. Its strong flavor is often described as syrupy sweet. Black truffles also are used for producing truffle salt and truffle honey. 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 make the most of this valuable ingredient. A few restaurants, such as Philippe Rochat in Switzerland, still stamp out circular discs of truffle flesh and use the skins for sauces.