- I think that only daring speculation can lead us further and not accumulation of facts. Albert Einstein
Hunt for Truffles
Truffles grow below ground with most providing no visible surface indication of their location, apart from the characteristic truffle aroma. Humans, having a relatively poor sense of smell, are unable to locate truffles without assistance, or only by the merest coincidence. Due to their concealment, truffles cannot be collected like mushrooms but have to be hunted, much like trying to find buried treasure, and there are several ways for the truffier (French for truffle hunter) to go about this.
Mouche method - truffle fly
A more effective but challenging technique is to follow truffle flies. Several species of tiny fly (Suilla sp) are drawn to truffles and are a good indicator of their whereabouts. Unlike insects in the soil, however, the flies are attracted to mature rather than younger truffles. The technique is to seek out these flies and let them lead the way. The flies are either in search of a mate or females seeking to lay their eggs directly above the truffles as a source of nutrition for their larvae after hatching. The truffle fly (Suilla pallida) is more elegant than the housefly, light-coloured, with long wings and a less energetic flight. If female it will be heavy at this time with eggs ready to be laid. The flies tend to appear on dry, sunny days when the weather is mild and locate the truffle with sensory organs in their antennae.
A truffle fly
During the truffle season, the flies hover around the base of trees where truffles abound. If the ground is cracked and partially exposes the truffles, the flies will gather in swarms and stumble across the ground to position themselves directly above the truffles. In this situation the truffle aroma is detectable by humans when the nose is pressed just above the ground where the flies have gathered. Sniffing along the cracks for the strongest intensity will locate the truffles. The fly is very determined about its truffle spot, often staying for long periods, and will tolerate subtle human presence at close proximity (a few centimetres) if no sudden disturbing or threatening movements are made. Sometimes, two flies will arrive above a truffle at the same time and fight for the site, tussling and rolling about until one gets tired and leaves to find another truffle. During all this frantic activity, the flies carry off the spores, helping to spread them between truffles.
When flies appear in isolation, they can be found in the low grass around truffle host trees. Truffiers approach at a low crouch, with the sun directly behind them and gently probe the grass for flies with a long thin branch; if a fly is already visible, the truffiers just wave the stick in its vicinity. When disturbed the fly will move to another spot close by, about a metre away, staying low, about 30cm above the ground. The original spot may then be investigated by clearing away any leaf-litter and pressing the nose to the ground to catch the aroma; otherwise waiting a few minutes will allow the fly time to return slowly to the original spot and confirm the positioning more precisely. After the fallen leaves have been cleared away, digging is done slowly with a small shovel, gradually uncovering the soil in shallow layers and the site thoroughly searched; large clumps of soil are broken up in case truffles are lodged inside. Throughout the digging process, the truffier sniffs the ground repeatedly by sticking the nose into the hole and inhaling deeply to gauge the intensity of the aroma until the truffle is found and recovered.
Alternatively, each spot a fly clings to can be marked with a twig and then, when sufficient spots have been marked this way, they can all be excavated for truffles together. This technique is only practical for working small areas and is not suitable for large plantations. Of course the fly does not appreciate losing its truffle to human hunters, especially if it has just won a fight over it and, although it is capable of finding another truffle, some spots should not be dug to enable the flies to complete their life-cycle and ensure they return the following year.
Raking method (American)
Truffle species in North America grow just beneath the surface of the ground (a few centimetres deep), at the interface between organic litter and mineral soil, and often form visible bulges or even protrude partially above the surface in cracks or where some soil erosion has occurred. They are also very plentiful. American truffiers do not use animals (pigs or dogs) to find wild truffles, but simply rake them out of the ground.
In north-western America, particular in the state of Oregon, white truffles growing at the base of douglas trees are recovered by raking the conifer needle-leaf litter to get to the truffles. Truffiers select areas where pure stands of young coastal douglas trees (Pseudotsuga menziesii) grow. Small rodents, usually squirrels and chipmunks, dig little pits at the base of these trees to recover the truffles. The truffiers search for recent pits that are not part of the animals’ burrows and the leaf-litter around the fresh pits is raked away to uncover more truffles. After the leaf-litter is cleared, the soil is raked down to a depth of 8-10 cm, while keeping careful watch for the light beige coloured truffles that contrast well with the dark brown soil.
Chef Janette Sinclair from Dallas hunts for both types of Oregon white truffle in a forest of douglas trees with mossy ground and no underbrush, near West Salem in Polk County. The truffles can be found in Oregon's Coast Range, the Willamette Valley and the foothills of the Cascades.
In south-eastern America, particularly in the state of Georgia, pecan truffles growing at the base of pecan trees are swept up together with fallen pecan nuts during the harvesting season and later separated and sold to local restaurants. The truffles are sought in more crowded, shaded sections on the east and north exposures and in the heavier clay soils of well-irrigated orchards. They may be adjacent to the trunk or anywhere further out to about the drip line of the tree, and are gathered by simply raking the surface of the soil with a stiff-tined (pronged) garden rake.
Raking is an inefficient method of harvesting truffles, as all specimens will be indiscriminately collected, including small, immature truffles with insufficient flavour. Truffles do not have the same importance in America as they do in Europe. The white truffles are only a minor food item in Oregon, and the pecan truffle crop is just a several thousand dollar supplementary item to the $100 million pecan nut industry in the leading producer state of Georgia. The American truffle crop is sold unsorted and has a reputation for poor flavour among local restaurants, which prefer to import proper European truffles.