The truffle is a hypogenous fungus, which lives underground and, like all mushrooms, has a root system formed by thick, branched thread-like stands of whitish filaments (hyphae) which spread throughout various substrate of the ground. The fruit, shaped like a tuber, is a fleshy mass, called "gelba," which is covered by a kind of bark, called "peridium." The structural features and colors of these parts make it easy to distinguish the various kinds of truffles.
A large proportion of the truffle is made up of water and mineral salts absorbed not only from the soil, but also through the roots of the tree with which it must live in symbiosis, because its lack of chlorophyll does not allow it to manufacture its own organic substances.
The white truffle of Piedmont varies in color, ranging from white, sometimes with pinkish veins, to brownish-gray, depending on the type of plant with which it grows and develops. It is known that this fungus grows when a piece of tree root is invaded by the threads of an underground mycelium, which in order to develop requires special saline conditions and soil humidity.
The roots most likely to cooperate with the mycelium towards the growth of a white truffle are those of the poplar, linden, oak and willow tree varieties and as some believe, the roots of vines.
After its formation, the truffle becomes a real parasite, sucking from the soil to produce its particular smell, flavor and color. Thus, truffles that develop under an oak tree tend to have the strongest smell, while linden trees produce the most aromatic variety. The shape and texture of the truffle also varies by the kind of soil in which it grows into: when the ground is soft, the truffle develops into a rounded and smooth shape, while compact soil will produce a knotty, gnarled fungus.
The ripening season usually runs from the end of August through January, with each root exposed to the mycelium normally producing one truffle per year, provided it is not cut by the truffle-hunters by mistake, or by poachers who plough haphazardly through the earth without the help of dogs.
