Of about 50 truffieres in NSW, only a handful are actually producing truffles.

No one knows why some trees produce and others do not, it is one of the mysteries that surround the magical fungus.

When Col planted his truffiere with 530 English oaks, Ilex oaks and hazelnuts in 2002 he consoled himself with the knowledge that even if the truffi-ere didn’t bear fruit, the trees would be beautiful.

However, he dug up his first French Perigord black truffles in 2006. The seedling trees have to be inoculated in the nursery prior to being planted if they are to produce truffles.

Col Roberts was a forester for 20 years. When he retired he wanted an interest that would allow him to use his tree growing skills.

Now he eats, sleeps and breathes truffles. It is clear he loves what he does, so much so that he and his wife Sue sometimes need to have an occasional truffle-free day.

Col trained his own truffle dog Morris, a 3-year-old labrador who sniffs his way along the rows of trees until he smells a truffle deep in the earth. He is now training a second dog Sully who is just 18-months-old. He still needs a lot of work.

The 100 acre Oberon property where the couple have lived for the past 20 years has turned out to be the perfect place to grow truffles. Although he is only half way through the season he has already collected more truffles than last year.

“We’re lucky. Some people don’t get any truffles,” Col said.

“It’s the cold weather that brings them on.

“Soil is important too, but we don’t know how. We do know you have to modify the soil here with lots of lime.”

Truffles come in all shapes and sizes and they have their own grading system.

“Smell is most important. A really nice one will have a sweet smell,” Col said. “If there is no smell the truffle either isn’t ripe or it isn’t a truffle.

“A ripe truffle will be black and marbled. If it is a caramel colour it is not ready.

“Chefs like to shave them into wafer thin slices so a nice round truffle is good. You can get a lot of thin slices off one truffle.”

The first Australian truffles were grown in Western Australia and Tasmania 12-years-ago.

The Japanese and Koreans are the biggest eaters of Australian truffles. Chefs at the finest restaurants in Singapore and Hong Kong’s grand hotels also love Australian truffles.