Why Are Truffles So Expensive?

Truffles are found or excavated by gatherers. They are not farmed very successfully as the process of cultivating truffles is both time consuming and beset with problems. Even though a bearing tree can fruit for 30 years the tree begins its first productive cycle only 7 years after being planted. All cultivated stocks need constant replenishing. Truffle prices now range around hundred to two hundred pounds per pound.

Truffles are considered a delicacy in most countries of Europe. It has even been referred to as a diamond in ones kitchen. There is a constant demand for truffles.
There has a sever drop in yields of truffles due to their overexploitation. Yields no longer measure up to what was seen in the past.  

Animals such as pigs, especially wild ones compete with humans to get to the delicacy. This is even seen in the popular comics of 'Asterix'.