The Périgord truffle: what is it?
"Divine", "sublime", "precious", "marvelous"... Superlatives abound to talk about the Périgord truffle. For at least three millennia, a worldwide tribute has been paid to it even if the same words sometimes cover different realities. The set of praises around truffles includes, when we go back in time, all kinds of truffles: "black", "white", etc. From the table of the pharaohs and kings to that of the presidents, passing by those of the emperors, the holders of power like to serve truffles of Périgord to their guests. Starting with France where the courts of Charles V, Philippe le Bon, François I, and Louis XIV, to name but a few, were already in their time, lovers of this delicious dish.
The truffle, and more particularly the Périgord truffle, what is it?
Truffles belong to a large family of fungi that practice symbiosis. To do this, they need a host: the truffle tree.
With the famous black Perigord truffle, knowledge has progressed, especially in understanding its nutrition and reproduction. However, this mycorrhizal fungus that is the Perigord truffle, remains a real mystery on many aspects. What is commonly called truffle and more particularly, Perigord truffle, is in fact the fruiting body of the truffle also called "ascocarps". It can indeed exist, to the great displeasure of truffle growers, for years or even indefinitely, only in the form of a thin white filament that is most often called mycelium. The fruiting part, or ascocarp, of the Périgord truffle, which is called truffle by simplification, is only a fruit filled with spores (thousands or millions). This "flesh" including all the spores is called "internal gléba" as opposed to the "external skin" called "peridium".
What are the different varieties of truffles?
The common name of truffle hides a great mycological diversity. Methodological advances (genome sequencing, DNA typing and markers, phylogenetic analyses, etc.) have, by limiting themselves to the genus Tuber, allowed the identification of nearly 650 more or less recognized species, of which at least 30 have been validated in Europe, of which the best known are: the black truffle of the Périgord and the white truffle of Alba. Not all of them concern truffle growing in the strict sense of the word, but rather the mycology of truffle-growing areas in the world.
Let us recall that each species is identified by a genus name (Tuber) and a species name (e.g. melanosporum for the Périgord truffle) but which can be completed by certain authors with a designation of variants (e.g. uncinatum for the Burgundy truffle) showing that there can be a great variability within the same species. The Latin name is completed by an indication of the author of the "official" description, for example "Vittad" for Vittadini. This Italian mycologist deserves a special mention, and was an example of the original descriptions of European truffles in the 19th century.
The Latin name is an important element for the labeling of truffle products.
Le Tacon (2017) proposes to divide the genus Tuber into 7 major groups. Here we will only mention the main groups to show the "relationships" that can exist on the phylogenetic level while the traditional, morphological or gustatory criteria create differences of a completely different order.
We will see here the 7 main types of truffles:
- The Périgord truffle
- The brumale truffle
- The summer truffle
- The Bourgogne truffle
- The mesenteric truffle
- The white truffle of Alba
- The white truffle
The group including tuber melanosporum, the scientific name of the famous Perigord truffle includes without surprise the brumale truffle (tuber brumale) but also tuber indicum, the so-called Chinese truffle (which we will not talk about here as it is of no interest)! The tuber aestivum group includes of course the summer truffle and its variants such as the so-called "Burgundy" truffle (still referred to as uncinatum), the Meuse truffle (tuber mesentericum), but also tuber magnatum, the white truffle of Italy.
The white truffle (tuber borchii), which has become commercially important in Italy and exists spontaneously in France, belongs to a group that includes several American, Asian and European species (including T. maculatum). For the record, the other groups, of which we will not speak here as their quantity is insignificant, are: Rufum, Macrosporum, Excavatum, Genadii. We can also classify the different races of truffles according to their colors:
The truffles with black dominance:
Melanosporum family, where we find the Perigord truffle or black truffle (tuber melanosporum), but also the brumale truffle (tuber brumale) and the Chinese truffle (tuber indicum);
Family Aestivum, with, in addition to the summer truffle (tuber aestivum) stricto sensu, the Burgundy truffle (tuber uncinatum) as well as the mesenteric truffle (tuber mesentericum).
The so-called "white" truffles (in fact yellow ochre) Magnatum family, with a famous species, the white truffle of Piedmont or Alba truffle; Puberulum family, with edible species such as the so-called Borchii truffles (tuber borchii), but also the American truffle (tuber gibbosum)
List of the different species Black Truffle of Périgord : Tuber melanosporum (Vittad.) Let's start with the queen of our markets.
You will be able, and it is there perhaps where that complicates, to find it under various names:
Black Truffle of Périgord
Truffle of Périgord
Or simply Truffle!!!
So many names (or vernacular name for the intimates...) to designate the same race of truffle. The biggest problem, with this quantity of common names, is that one can easily be mistaken. Indeed, let's take the summer truffle or even the Burgundy truffle, (respectively tuber aestivum and tuber uncinatum) which also have a skin (called peridium) of dark brown to black color, traders have the right to communicate on these products by writing "black truffle" because it is a truffle is that it is black, outside, but black anyway. This is why throughout this article we will put the common name as well as the scientific name of each truffle we talk about. Because to be sure of the type of truffle that makes up each product, the only solution is to read the composition of the product and look at the scientific name of the truffle that makes it up. Let's go back to the Périgord truffle (tuber melanosporum), the noble species par excellence, the reference for the consumer. It is called "black truffle of Périgord" by botanists since the eighteenth century, a somewhat chauvinistic appellation because its natural distribution area goes from Andalusia to Picardy and from the Atlantic to Croatia. The harvest of the Périgord truffle (tuber melanosporum) is done from November to March, however early specimens are detected as early as August or September (branded truffles or flower truffles). There are two natural subpopulations in the west and east of the Massif Central, but the spread of mycorrhizal plants has probably led to a mixing of species within the plantations.
The fruiting body of the Périgord truffle (tuber melanosporum), harvested from November to March, is black, but presents, at the base of the scales, reddish zones before maturity. It can reach a diameter of about fifteen centimeters and exceptionally exceed one kilogram. It is characterized by an external surface (peridium) formed by warts (or scales) in pyramid and black at maturity. When the Perigord truffle (tuber melanosporum) is cut, the famous "canifage" of the auctioneers, the tissues (gléba) have a black to brown aspect, interspersed with fine and branched white veins. The scent is intense and persistent in an enclosed space such as a kitchen, a car, etc. It is specific enough to have been retained as a type of tertiary aroma of red wines and also, of course, to justify the attraction of gastronomes.
The spores of the Perigord truffle (tuber melanosporum) can be seen under the microscope. The spores are dark brown, ovoid with short spines, their number per asci is very variable, usually 4 or 2, but sometimes 1, 3 or 5. The mycorrhiza (the association between the plant and the fungus) of the Perigord truffle (tuber melanosporum) is visible to the eye or with a magnifying glass on the roots. The structures have a characteristic club-like shape, sometimes grouped in glomerules.
The cells forming the surface of these clubs (mantle) are organized in "puzzle pieces"; the mycelial filaments extending from them to explore the soil (called spinules or sometimes cystids) are straight or branched at right angles.
Truffle called "brumale" or truffle: Tuber brumale (Vittad.)
This truffle has been, and still is sometimes, confused with the Perigord truffle (tuber melanosporum) because its appearance is similar. It is present at the same winter period, in the same geographical areas, but it can also be more northern (described in Great Britain) or continental up to Hungary. The species seems to be more plastic, tolerating differences in soil quality (acidity, hydromorphy, clays...). It is considered a formidable competitor to the Perigord truffle (tuber melanosporum) and sometimes remains an unintended (but edible) product of
cultures. The size is usually smaller than that of the Perigord truffle (tuber melanosporum). The external peridium is dark black. The scales are generally finer than those of the Perigord truffle (tuber melanosporum). A fingernail scraping reveals a useful difference in the market; the surface of the peridium is removed in flakes or scales while that of the Perigord truffle (tuber melanosporum) remains intact. The internal gleba is lighter with larger white veins. The scent is also deceptive; it is often quite similar to that of the Perigord truffle (tuber melanosporum) although more discreet; sometimes, it can also be frankly repulsive. This species is sometimes called "musky truffle" because some ascocarps can give off an unpleasant odor without the reasons for this variability being known. The spores are also elliptical to ovoid, light brown in color. The difference with the Perigord truffle (tuber melanosporum) lies in the long spines. For the mycorrhizae: the clubs are quite similar to those of the Perigord truffle (tuber melanosporum), generally lighter. The difference lies in the peripheral spinules which are shorter and rarely branched.
Summer truffle and Burgundy truffle : Tuber aestivum and Tuber uncinatum (Vittad)
For a long time considered as two different species (respectively called summer truffle and Burgundy truffle), modern biology now leads to consider only one species with variants. In practice, this poses a problem because, to date, the name used on the market does not coincide with the scientific nomenclature, which should be the law in case of litigation! For the sake of simplicity, we will treat them as two biological types of the same species, widely spread in Europe as far as Scandinavia, Ireland, Hungary, Bulgaria and Turkey.
They can sometimes cohabit with the Périgord truffle (tuber melanosporum) in truffle fields in the process of closing the aerial parts or be present on the roots without fructifying. They prefer high density forest environments (more than 1,000 trees per hectare and with a diversity of species). The summer truffle (the aestivum type) can be harvested almost all year round, with a major period from the end of May to September. The Burgundy truffle (the uncinatum type), on the other hand, is considered ripe from late August to December. The precise description of the fruiting bodies according to the external aspect is delicate because there is a great variability according to the environment and the season of development.
For both types, the ascocarps have a shape and size quite similar to those of the Périgord truffle (tuber melanosporum), with a black to brownish color at maturity. The scales or warts are pyramidal with edges generally quite angular for the Burgundy truffle (tuber uncinatum). The internal gleba evolves with the maturity, from the dominant white to a mixture of brownish zones (sometimes chocolate or greyish) and white veins in opposition to the Périgord truffle (tuber melanosporum) which has the dark brown to black gleba. The difficulty comes from the stages of harvesting. Indeed, the summer truffle (tuber aestivum) is often harvested before complete maturity, with a predominantly white gleba which can justify the common name of white truffle (summer). In fact, when mature, both types have an almost similar appearance to the cut, generally a little darker for the Burgundy truffle (the uncinatum type).
The scent also depends on the stage of harvesting; in its white form, the summer truffle (the aestivum type) has a sweet smell of yeast, or even of button mushroom. In this case, there is no confusion with the Perigord truffle (tuber melanosporum). When fully mature, both types and especially the Burgundy truffle (the uncinatum type) have a specific scent, some of which may remind us of the Perigord truffle (tuber melanosporum), but where we find a hazelnut smell that makes its taste specific.
In November or December, when the Burgundy truffle (tuber uncinatum) and the Périgord truffle (tuber melanosporum) can be presented together on markets, there is a real difficulty of recognition "by eye" except for technicians and brokers.
The distinction with the Périgord truffle (tuber melanosporum) or the brumale truffle (tuber brumale) is immediate when canifage or even better under the microscope because both types, summer truffle (tuber aestivum) and Burgundy truffle (tuber uncinatum) have spores decorated not with spines but with alveolus structures, polygons of five to six unequal sides. These alveoli are said to be taller for the Burgundy truffle (tuber uncinatum), but this kind of microscopic measurement is the domain of specialists.
As for the mycorrhizae, the organs formed with the root are (in general)
cylindrical, often with a dense surrounding of mycelial filaments (less club-shaped and more "fluffy" than in the Périgord truffle (tuber melanosporum)). The obvious difference with a magnifying glass concerns the surface cells of the mycorrhiza, which are polygonal in shape in the summer truffle (tuber aestivum) or the Burgundy truffle (tuber uncinatum) and in the form of rounded "puzzle pieces" in the Perigord truffle (tuber melanosporum).
Mesenteric or Meuse Truffle : Tuber mesentericum (Vittad.) This species, long neglected in France, is once again being harvested (Truffle of
Meuse), markets and cultivation trials, particularly in the east of the country, although it is known throughout Europe and sought after in Italy, among others, under the name of Bagnoli truffle. Its ecology is very similar to that of the Burgundy truffle (tuber uncinatum), but it is harvested in winter. Generally smaller than the Perigord truffle (tuber melanosporum), it is black in color with a hole at the base (basil dimple) that can form a cavity communicating with the outside (once cut, it can remind a kidney). The internal gleba is brown-gray or chocolate, larded with tortuous white veins. The "perfume" is very specific, tincture of iodine for some, phenolic for others, attenuating after harvest. These truffles are sought after by pork butchers to give an original taste to pâtés.
The spores are ellipsoidal to spherical, rather clear or translucent, with irregular ornamentation in cells or reticules. The mycorrhizae are in cylindrical clubs, with polygonal cells and spinules giving
often with the magnifying glass a shaggy aspect because of ramifications.
White truffle of Alba : tuber magnatum pico. The white truffles of Alba (tuber magnatum pico.) belong to the Italian gastronomic tradition in opposition to the truffles of Perigord (tuber melanosporum) which are more of French origin. The prices on the markets, the media coverage, such as the delivery of truffles to the Pope, or the phenomenal auctions, make people dream even outside the Italian peninsula, especially since the harvest of the white truffle of Alba (tuber magnatum pico.) in the wild in the Drôme in 2011. Recently, there is a commercial offer of plants mycorrhized with this prestigious species and small plantations are made in France. Tuber magnatum is called white truffle of Piedmont or truffle of Alba because of the quantity found in these regions approaching almost 100% of world production. Their culinary interest is specific and prestigious for the white truffle of Alba (tuber magnatum pico.). This species is not yet commercially produced in France from crops. Of yellowish-gray color, smooth, the size of the white truffle of Alba (tuber magnatum pico.) can reach 12 to 15 cm with a weight exceeding sometimes 500 g or the kilo. The record still today is 2.7 kg! The gleba is whitish to ochre with strong variations. The smell of the white truffle of Alba
(tuber magnatum pico.) is sweet and comes close to the smell of garlic cheese. But it is a question of taste and culture! The period of maturity arrives around autumn. Of ellipsoid to spherical shape, the spores of the white truffle of Alba (tuber magnatum pico.) are rather light brown, with an irregular ornamentation in reticules.
The mycorrhizae of the Alba white truffle (tuber magnatum pico.) are in the form of cylindrical clubs, with polygonal cells and spinules often giving to the magnifying glass a shaggy aspect because of ramifications.
Truffle known as "white": tuber borchii
The white truffle (tuber borchii) is sometimes found during earthworks, for example in the alluvial terraces of the rivers of the South West, Garonne, Lot.
It is yellowish-gray in color but darker than the white Alba truffle (tuber magnatum pico.), and is also more granular. The size of the white truffle (tuber borchii) is much smaller, from 4 to 7 cm for 10 to 150 g. The gleba is whitish to ochre with strong variations which can go until the brown. The perfume is strong and of type acetylene. The periods of maturity arrive as for the truffle of Périgord (tuber melanosporum) at the beginning of the winter the spores are as for the white truffle of Alba (tuber magnatum pico.) of ellipsoidal to spherical form, rather light brown, with an irregular ornamentation in reticules.
Same as for Alba white truffle (tuber magnatum pico.) mycorrhizae are in cylindrical clubs, with polygonal cells and spinules often giving to the magnifying glass a shaggy aspect because of ramifications.
Are all truffles edible?
Be careful, out of the 650 species of truffles referenced today, only a few have a real gustatory interest. And potentially some can even cause gastric and intestinal disorders that can lead to hospitalization depending on the type and quantity you ingest. It is above all a mushroom so as for all the others be careful and ask experts if your harvest is the right one.
What are the best truffles?
There are no truffles that are better than others, although the two queens of our plates are the white truffle of Alba (tuber magnatum pico.) and the truffle of Périgord (tuber melanosporum). It all depends on what you want to do with them and the price you want to pay. To answer these questions I advise you to take a look at our two articles which
will easily answer your questions:
Truffle: the best recipes, everything you always wanted to know about cooking with truffles.
Price of the truffle: Why is it so expensive?
Which truffle has the most taste?
Without a doubt, here are the truffles with the most gustatory interest in order:
- The Perigord truffle (tuber melanosporum)
- La truffe blanche d'Alba (tuber magnatum pico.).
- The truffe brumale (tuber brumale)
- The summer truffle (tuber aestivum) and the Burgundy truffle (tuber uncinatum)
Where to visit a truffle farm?
Some people who love truffle growing offer to visit their truffle fields, but if you really want to discover in depth all the aspects of the Périgord truffle.
Why is the Périgord truffle rare?
A little history of the Périgord truffle and its cousins The cultivation of the Périgord black truffle is quite complex to identify during antiquity and the Middle Ages because of the little documentation on the subject that we have left from that time.
However, we can be certain of one thing: the destruction of the vines by phylloxera during the 19th century forced the winegrowers to turn to another type of cultivation; it was at this time that truffle growing experienced a significant boom. But the phylloxera invasion alone does not explain the production figures reported by Chatin in 1892, concerning the year 1868 (before the phylloxera invasion) for the departments of Vaucluse (380 tons), Basses-Alpes (300 tons), Lot (300 tons), Drôme (120 tons), and Dordogne (120 tons), i.e. 50 to 100 times the current production of these same departments. Even if these figures are undoubtedly overestimated (perhaps twice as much) due to the mixing of truffle species and probable confusion over the units of measurement of weight, these productions can be considered as the result of a planting process spread over several decades. The phylloxera has given the truffle a vast territory ecologically at its optimum. In many regions, the soils abounded in truffle spores due to the large number of spontaneous truffle beds in an open environment. This ecological capital was quickly put to good use by farmers, sometimes ruined wine growers, sometimes simply farmers and breeders. Some families in the Lot produced a ton of truffles in 1906, a quite exceptional year.
Until the First World War, the truffle growers exploited this manna. The bleeding of the peasant population during the 1914-1918 war was the beginning of the decline of truffle production. During the war, the women devoted themselves to food crops, leaving the truffle fields behind. After the war, truffle growing was penalized by a loss of practical knowledge due to the disappearance of men in combat. The transmission of knowledge was rarely from men to women because truffles were essentially a male affair. The truffle production, which had been integrated for a long time to the farm, will gradually become a side business. The increasing rural exodus will contribute to a loss of available manpower for the maintenance of truffle fields. In 1940, France produced 435 tons of truffles against 985 tons in 1914. The decline was underway. But at the end of the Second World War, more important causes will play with the establishment of the Agricultural Policy, food agriculture gives way to an industrial agriculture.
The Périgord truffle today The 1964/1965 harvest was still at 150 tons. Today, even at a much reduced level compared to the 19th century, the production of winter truffles still fluctuates greatly from year to year, depending on climatic conditions (prolonged drought, frost...). Globally, the variations of the production for Perigord truffle (tuber melanosporum) go from 15 to 70 tons for France, from 5 to 80 for Spain (in great progression for some years) and from 10 to 70 for Italy. In total, the European harvest (limited to these three countries) is in an extreme range of 30 to 220 tons...
Other truffles nowadays :
For the white truffle of Alba (tuber magnatum pico.), the Italian harvest can vary from 5 to 50 tons depending on the year. The harvest of the summer truffle (tuber aestivum) and its cousin the Burgundy truffle (tuber uncinatum) is more stable (between 50 and 100 tons) and comes more from natural truffle fields.
The effects of the policies of revival of the truffle culture appear gradually: the entry
The production of new plantations leads to a rise in the annual production floor when climatic conditions are bad. When they become more normal, French production exceeds 60 tons. In 2017-2018, despite a persistent drought in the Southeast, the French harvest was about 30 tons; in the late 1990s, it was 20 tons.
Truffle in France
La production de nouvelles plantations entraîne une augmentation du plancher de production annuelle lorsque les conditions climatiques sont mauvaises. Lorsqu'elles se normalisent, la production française dépasse les 60 tonnes. En 2017-2018, malgré une sécheresse persistante dans le Sud-Est, la récolte française a été d'environ 30 tonnes ; à la fin des années 1990, elle était de 20 tonnes.
declined before straightening up.
Today, it is estimated that more than 20,000 hectares are planted in France.
Plantations have resumed in France since the 1970s with the appearance of the mycorrhizal plant. But then, why is it so complicated to grow Perigord truffles? To succeed in growing Perigord truffles, a large amount of parameters must be gathered.
- A soil with a well-defined quantity of limestone, a rather basic pH but not too much,
– 3 à 6 % de matière organique dans le sol
- A not too hot summer with regular rainfall,
- An autumn with a good regular precipitation but without it being too abundant,
- A winter without too much frost
- And much more
All this shows how difficult it is to obtain truffles. Especially since even if one tries to maximize the chances by choosing selected mycorrhizal plants, the number of trees giving a truffle one day is rarely higher than 5%.
What are the most expensive truffles?
Without a doubt the most expensive truffle per kilogram is the white truffle of Alba (tuber magnatum pico.). Count on average 5000 € per kg and between 2500 and more than 9000 € per kg depending on the season and the date of your purchase. That is to say approximately 5€ the gram.
Then comes the Perigord truffle (tuber melanosporum) which will vary from simple to triple depending on the date you will buy your truffle. Count on average 1000 € the kg with a variation which goes from 500€ to more than 2000€ according to the date and the place of your purchase. That is an average of 1€ per gram. The truffle of Burgundy also oscillates between 400 and 600 € the kilo Then come the truffles brumale oscillating generally around 300 to 500 € the kilo. The summer truffle as for itself so very close to the truffle of burgundy is sold between 150 and 250 € the kilo
Is the truffle really that expensive?
We can see the disparity of price that there can be between the type of truffle, the weight of course, if the season is good or not and finally the date of your purchase. Indeed, buying a Perigord truffle on Christmas Eve or New Year's Eve or in the middle of the month
We can see the disparity of price that there can be between the type of truffle, the weight of course, if the season is good or not and finally the date of your purchase. Indeed, buying a Perigord truffle on Christmas Eve or New Year's Eve or in the middle of the month
But if you are smart and patient, you will wait for the right period and you will manage to buy them at the best price.
Especially since to make a good dish, if you use the right methods and tricks, with only 5 to 10 g of Perigord truffles per dish and per person you will be satisfied. If you want to know more about how to prepare the Perigord truffle you can see our article: Truffle: the best recipes, everything you always wanted to know about cooking with truffles
And yes indeed, very few people buy Périgord truffles by the kilo. You have to think of it as an exceptional condiment. Have you ever bought a kilo of dried chives, or a kilo of dried dill? No, and that's normal. Well, it's a bit the same for truffles. 5 to 10 grams per dish per person at 800 € per kilogram can be scary but when you calculate it's immediately better. That makes an average of 6 € per person. That's better, isn't it? Indeed you will not eat it every day but to please yourself, knowing that the Périgord truffle goes best with simple things like pasta, eggs or even potatoes, you will succeed in making a magnificent festive dish for less than 10 € per person.