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zoomed in view of a lot of truffles

Gold in the Soil: Truffles

What are Truffles?

A truffle is, in the simplest terms, a fungus or mushroom of the genus Tuber. It grows underground, typically near or right beneath the roots of trees, particularly oak, beech, birch, poplars and pine trees. They form a symbiotic relationship – meaning the tree and the truffles both get something out of the relationship, sugars and nutrients. Chefs who use truffles usually shave or slice them raw over dishes, including pastas, rice, salads, eggs, and meats. They can also be infused into sauces, soups, cheese, butters, and oils.Do not put truffles in sealed plastic bags. If you do they will mold, get slimy, and smell bad! Never eat any truffle or other fungus unless it is identified by an expert. You might confuse the button stage of a poisonous mushroom with a truffle, or be allergic.

Truffle Hunting in Europe

Truffles are difficult to find and very expensive as a result! In 1994, black truffles sold for $350 to $500 a pound. In the United States, edible truffles are collected in the forests of Oregon and Washington. In Europe, most truffles are collected in France and Italy. Truffle hunters in Italy and France use pigs and mixed-breed dogs to sniff out truffles. Dogs are preferred to pigs because pigs love to eat truffles. The hunters use a staff to force the pig to back off, once the pig has located a truffle.

In Italy, truffle dogs are trained in several steps. First, the dog is taught to retrieve a rubber ball. Next, a small bit of smelly Gorgonzola cheese is substituted for the rubber ball. After the dog has learned to retrieve the cheese, the cheese is hidden, forcing the dog to sniff it out for a reward of food. Finally, a small truffle is substituted for the cheese. The dog is trained to fetch, then dig up the truffle. Dogs like other food better than truffles, so bread and other treats are used for rewards. The night before a truffle hunt the dog is not fed so it will be eager to find truffles for the treat. Some dogs take the easy way out. They find and eat garbage buried by campers! Dogs generally do not find young truffles because the odor is too weak. The odor becomes stronger with age as the spores mature.

The value of commercial truffles means that there are laws controlling their collection. In Italy, for example, truffle collectors are tested and licensed. There, organizations of land owners called cooperatives control truffle hunting on their property. Unless you are a member of the cooperative, you can be arrested for collecting truffles from cooperative truffle beds.

Truffle Hunting in America

In North America, truffle collectors use three major clues to find truffles. First, it must be warm and the soil moist. Truffles are often found 10 to 14 days after a heavy rain. The umbrella shaped mushrooms which pop up after a good rain can be used as a kind of clock. Look for truffles after these mushrooms have started to collapse.

Second, the right trees must be present. Truffles are formed by fungi that are partners (ectomycorrhizal) with certain trees. You will not find truffles under maples, for instance, because maples do not form ectomycorrhizae. Trees to use as clues include: pines, firs, Douglas-fir, oaks, hazel nuts, hickories, birches, beeches, and eucalyptus.

Third, truffles use animals for spore dispersal. In North America, squirrels and chipmunks are the major wild animals dispersing truffle spores. Search among the right trees for pits dug by rodents in their own hunt for truffles. Pits do not guarantee success, however, rodents also dig pits searching for acorns, onion bulbs, and beetle grubs. The best success results from raking around fresh pits. Look for pits not filled with leaves or other debris. I use a four-tine garden cultivator with the handle shortened to 30 inches to rake leaves off the surface and dig into the soil 3 or 4 inches (8 to 10 cm) .

A good eye is required as many truffles are small and colored red, brown, white, or even black. Bring a supply of small paper bags for taking your truffles home. Write your collection notes on the bag before putting the truffles inside it. Information on fresh appearance and habitat is often needed to identify fungi. Note the color and shape of the truffle, and what kind of trees are close by. The date and precise location are also useful information. These data can help you understand when and where to look next year.

Black truffle cut with a knife
Truffle hunting with dogs
hands holding white truffles
Truffle hunting with a pig