Truffles are the fruiting bodies of fungi that grow underground, in association with a host plant. There are many species of truffle in the world, with only a few of recognised culinary value. It is estimated that there may be as many as 2000 species of native truffle in Australia, with only 300 scientifically described so far, and none known to be of culinary significance.
Several species of truffle grow naturally in Europe that have become prized over the centuries for their unusual and sensuous flavour and aroma qualities. The Perigord black truffle (T. Melanosporum) is one of the most well-known of these, and, as natural supply diminishes for various reasons, they are being widely cultivated using technologies that have only recently been employed.
Australia is now the fourth biggest producer of tuber melanosporum globally, but many other countries are entering this activity. There is still much that is unknown about these fungi, and success in cultivation is nowhere near as certain as it is, for example, with other commercially available mushrooms and fungi. Therefore, the activity is high risk and requires several years of patience to determine success. By and large, domestic use is a cottage industry in Australia, with a few large, 'corporate'-style operations serving the export trade.
You may think that truffles are a relatively homogeneous product (albeit of high value), but in fact, there are regional variations in the truffles grown in Australia, as well as specific qualities from individual truffieres. This seems to stem from the different soil types, climatic conditions and other aspects of 'terroir'. This has led some growers to brand their truffles, as we have done: Buxton Black Truffles.
Now entering our tenth year since planting, Buxton Black Truffles have been recognised by the chefs we supply as superior in aroma and flavour to many others on the market. We believe our rich soil, high in organic matter, and our temperature variations (hard frosts) are some of the reasons for that.
The edible part of this mycorrhizal fungus is the familiar black, textured mass, which may be smoothly shaped or highly irregular, with textured skin that can be fine-grained to 'warty'. This is the fruiting body of a fungus that is otherwise a very fine network of cells that grow around the fine roots of the host tree. ("Myco" from the Greek for 'fungus' and "rhiza" from the Greek for 'root'.) This fungus lives in a symbiotic relationship with its host tree, with each participant giving and getting moisture and nutrients in a mutually advantageous way.
Like other familiar mushrooms and toadstools, black truffles are the fungus's way of reproducing. Essentially the truffle is filled with spores. The distinctive aroma given off by the ripe truffle is its means of attracting animals to eat it and pass its spores through their digestive tracts and spread the spores around the countryside.
The truffle fruiting body begins to form in Spring and grows in the soil according to the available food and moisture through Summer. Truffiere owners must make decisions about irrigation of truffles during dry periods in the absence of data that can be a reliable guide to its effect. (Some believe that irrigation assists truffle rot.) By Autumn the truffle has generally reached its size, and it waits until the onset of shorter days and colder temperatures (especially frosts) to begin ripening.
You would need to dig up many unripe truffles to monitor this stage of development, and truffle ripening may cease if interrupted at this stage (even a slight disturbance would intervene), so relatively little is known about it. Therefore, we wait for the distinctive aromas of the ripe truffles to be available to our dogs and our own noses. Like a climacteric fruit, a mature truffle will continue to change after harvest, but this may not be a true ripening phase, but rather a process of deterioration. There is a relatively short window when most advantage can be taken of the truffle. See notes below on keeping truffles after harvest.
You will know best how you wish to prepare food you enjoy, but here are some things to consider about using black truffles.
As a perishable food, it is best to use the truffles within 1 to 7 days after harvest. When maintained well, they can still strongly enhance your food for another 7 to 14 days after this period, although their power will gradually fade. So plan ahead to maximise your use of the truffle. See keeping notes below.
While potent when fresh, truffle flavour and aroma are subtle influences in food and are easily reduced or eliminated if not used in the right way. Heating truffle above a certain temperature will often destroy the aromatic qualities; for example, when cooked with roasting meat, the truffle may be hard to detect in the final result. They are therefore best added after the main cooking to still-warm foods, either to be lightly cooked or added as a fresh ingredient.
Truffles enhance other subtly flavoured foods, like potatoes, pasta, eggs. For example, finely slice or grate truffle into mashed potato in the final stages of preparation (after the potatoes are cooked), and add an appropriate amount over the served portion on the plate. The best results with scrambled eggs are often achieved when they are slow-cooked over a moderate heat, with truffle grated into the mixture and over the final portions. (You can store the uncooked eggs in their shell for a day or two in the container with the truffle in the refrigerator, and the eggs will take up the aroma.) Likewise, add truffle to pasta dishes in the final stages of preparation of the sauce, or directly over the steaming pasta on the plate.
A truffle shaver allows very fine slices to be achieved, and certain graters or microplanes can produce distinct pieces without mashing the truffle. Truffle does not need to dominate, and relatively small amounts can add a deep, earthy undernote to the flavour of your dish.
A truffle is ideally harvested near the top of its ripening cycle. When it is harvested, it is cleaned with water and a vigorous brushing with a moderately stiff-bristled brush to remove the earth and to allow grading and checking for ripeness (a small grading nick is made in each truffle.)
Its potent aroma and flavour will continue to increase for a few days after it has left the ground, and then will fade over time. Truffles should be kept chilled (but not frozen) in a sealed container that contains some material to absorb the moisture given off by the truffle. This can be, for example, dry paper towel or uncooked white rice. Truffles lose about 1 percent of their weight as exhaled moisture per day. Change the paper towel as needed, but at least every one or two days. Moisture on the surface of the truffle should be dabbed off with a paper towel. (If there is excess moisture, it is OK to use a hair dryer sparingly to remove it.) White rice may then be cooked, and may retain some of the absorbed truffle flavour.
Snap-lock plastic containers or glass jars with rubber-sealed lids are good for keeping truffle in your fridge without its aroma permeating other foods. Occasionally small amounts of white mould grow on the surface of the truffle. This can be brushed or washed off, and truffle can be used as you normally would. You only need to use what you need for a given dish, and then return the unused portion to the container.
While there are some 'classic' truffle aromas, they can exhibit a range of different aromas that you may or may not find appealing, such as shoe polish or iodine/salt sea. Many of these are 'normal', but also may indicate the beginnings of break-down of the truffle. If you detect 'off' aromas or find that there is internal moisture and softness/sponginess, you can carve away the affected parts with a sharp paring knife, and continue to use the parts that seem sound.
Truffles are a natural product, and therefore quality varies. If you are in doubt about using any of your Buxton Black Truffle, please contact us to discuss.