Truffles and Terroir
Food and wine lovers know the importance of terroir in wine production; we believe that the connection is even more vital to produce high quality truffles.
If you have been fortunate enough to experience truffles from different regions of Australia and/or around the world, you may have noticed that the flavour and aroma varies greatly. This relates to the terroir where the truffle was produced, soil being the most important factor. You may even expect truffles grown in rich fertile soil to have a stronger flavour and aroma than those grown in poorer soils? Not so.
To understand why, you will first need to know a little more about the biological side of how the truffle develops. Tuber Melenosporum, more commonly known as the prized Black Perigord Truffle, is a variety of mycorrhizal fungi that form a symbiotic relationship on the roots of several varieties of host tree. The most common hosts are varieties of oak and hazel, which also contribute to the flavor of the truffle. Many varieties of Mycorrhrizal fungi are actually very common and are found on about 80% of the Earths wild plants. The fungi spores attach to the roots of the host and form networks of microscopic fibers called hyphae that form large networks that reach where roots cannot. The hyphae help the plant absorb water, mineral salts and nutrients for strong growth. A truffle is formed when these branches meet underground in clusters of hyphae called mycelia. The truffle is the resulting fruit body of this subterranean fungus.
The black Perigord truffle is a rare species of mycorrhizal fungi that has adapted to living in poor soil conditions and actually thrives in calcareous soils. In these soils, the host tree is heavily dependent on the fungi to receive its water and nutrients. In turn the tree ‘feeds’ the fungus with carbohydrates that the truffle depends upon to grow and reproduce. A tree that is growing in nutrient rich soil has little need for the root like hyphae fibers of mycorrhizal fungi to absorb nutrients. Therefore the tree will be unlikely to feed them with carbohydrates to encourage their growth.
When this occurs the hyphae will be shorter and less diverse, offering less opportunity for a truffle to develop and less food to grow the truffle if it does. It would be reasonable to assume that these truffles would often be less prolific, will sometimes have less aroma, but most importantly will have much less flavour. Truffles in poorer soils however, that have suffered small periods of water stress, are more likely to posses a more intense flavor and aroma. These effects will be intensified if the truffle is also grown in the correct climatic conditions; that is cold winters and warm summers. So beware the truffle from the rich growing region and instead favour the poor cousin – you might be surprised at what you find…