Truffles have been enjoyed as a gastronomic treat for millennia but it is only in the last hundred years or so that they have been universally recognised as a fungus, a mushroom. Some thirty species of truffle are thought to exist but here at Le Gardian we are intending to raise just one – The Black Diamond (Tuber melanosporum) or Périgord truffle.

Truffles multiply by spores and observation of these under a microscope is the only absolutely certain way, short of DNA analysis, to distinguish one species from another. The black truffle or rabasse grows in a strange symbiotic relationship with the roots of several trees but oaks are the most productive, particularly the evergreen Holm Oak (Quercus ilex) and the deciduous Downy Oak (Quercus pubescens).

The truffle enables the tree to assimilate phosphorus and in return it receives sugars to enable it to grow. It does this by producing mycorrhiza (tiny 2 to 3mm swellings the colour and shape of a miniature date) which invade the tree roots. The truffle develops over many months and harvesting can begin as early as 15th November although tradition has it that the best truffles are to be found between mid January and mid February.