The truffle is a hypogeous fungus (a mushroom that grows underground); like all fungi, its roots are formed by a very dense, branched network of whitish filaments (hyphae), which extend over several substrates.
The tuber-shaped fruit - called “gleba” - is a fleshy mass protected by an outer skin known as the peridium, and the various types of truffle are easy to identify from the structure and colour of these components.
Truffles are mainly composed of water and mineral salts absorbed from the soil through the roots of the tree they live in symbiosis with.
The colouring of the white truffle of Alba depends on the tree it lives and grows with, varying from white, with pink nuances at times, to grey tending to brown.
The best conditions for the network of hyphae (known as the “mycelium”) to develop a truffle are mainly found around the roots of poplars, lindens, oaks and willows, as well - some say - as vines.
After it has formed, the truffle becomes an out-and-out parasite, sucking in the lymph that the roots draw out of the soil to extract aroma, flavour and colour.
The truffles with the most persistent scent and best keeping qualities are those that grow in contact with oaks, while the lightest and most aromatic come from linden trees.
Their shape - generally roundish - depends on the nature of the terrain: if the ground is soft, they become smoother, while if it is hard, the truffle struggles to find room and will become more gnarled and knotty.
Truffles ripen between the end of August and January, with each root generally producing only one truffle a year.