Truffles are held in high esteem in French cooking.
- White truffles are generally served uncooked and
shaved over steaming buttered pasta or salads. White
or black paper-thin truffle slices may be inserted
in meats, under the skins of roasted fowl, in foie
gras preparations, in pâtés, or in stuffings.
Because of their high price and their pungent taste,
truffles are used sparingly.
- Black truffles are far less pungent and more refined
than their white cousins.
The Midi - Southern France - has the sweet limestone
soils and dry hot weather that truffles need to grow.
In 1900 truffles were used by most people, and on many
occasions. Nowadays, they are a rare delicacy reserved
for the rich, or used on special occasions.
Looking for truffles in open ground is almost always
carried out with specially trained pigs or dogs. Pigs
were the used extensively in the past - and still in
the popular imagination - but nowadays farmers prefer
to use dogs, which do not eat the truffles. Both pigs
and dogs have keen senses of smell, but while dog's
must be trained to the scent of truffles, female pigs
or sows need no training . A compound within the truffle
resembles a sex pheromone of boars - to which the sow
is naturally attracted. It is possible that the attraction
that sows have towards these fungi prompted their discovery
by early human populations.
Truffles are generally found under certain trees -
they live symbiotically with the trees' root system.
Symbiotes of the truffle include oaks, holm oaks, hornbeam,
hazelnut trees and colurna. The average life cycle of
a truffle-producing tree is around 30 years
The truffle is a fungus that grows underground. It
forms in Spring between April and June. When it is born
it has the form of a tiny cup ( stade apothécioïde
), of which the edges will close up and form the Tuber.
The interior of the Tuber will grow veines stériles
then veines fertiles. This whole autonomous ensemble
is the gleba (body) of the truffle, coloured white,
and covered with a skin ornamented with small warts
or scales which, as well as protecting the tuber, contributes
to its respiration and nutrition.
After a period of inactivity, the hot periods in July
( thermal stress ) and the storms in August ( or irrigation
), will set off the growing cycle. If the amount of
water and heat are optimal, the nearly finished size
will be attained at the beginning of September . Inside
the gleba, the number of of asques ( sacks containing
the spores ) will increase. First hyalines (nearly transparent
the spores, which represent the seed of the fungus,
will little by little brown during the melanisation
process, which will end by the acquisition of aroma
and the maturity of the fungus
The zones of production of Tuber melansporum are between
4O and 47 degrees of latitude North. This species needs
a temperate climate with well marked seasons. During
its maturing phase it freezes underground at -7°
C. The ideal climate for truffles is:
- Winter with nights at -5°, and days between
1O° et 14°C
- Spring with alternating periods of damp and heat.
- Hot Summer interrupted by thunderstorms, especially
between August 1 and 15.
- An Autumn which is not too wet.
Tuber melanosporum is a resistant truffle, both against
drought and flood, but it is vulnerable during its growing
cycle to shortage and excess of water, either of which
can be fatal.
If truffles are not harvested, they will degrade and
rot, releasing asques which will set free spores. The
cycle will continue with the germination of a number
of spores, liberating of "hyphes" (or primary
mycélium ) likely to infect the rootlets of a
host tree by giving birth to new mycorrhizes.
Contrary to popular legend, truffles can be cultivated.
As early as 1808, there were successful attempts to
cultivate them, known in French as trufficulture.
People had long observed that truffles were growing
among the roots of certain trees, oak trees in particular,
and scientific research has established that truffles
live in symbiosis with the host tree. In 1808, Joseph
Talon, from Apt in southern France, had the idea of
sowing acorns collected at the foot of oak trees known
to host truffles in their root system. The experiment
was successful. Years later, truffles were found in
the soil around the oak trees grown from those acorns.
In 1847, Auguste Rousseau of Carpentras planted 7 hectares
(17 acres) of oak trees again from acorns found on the
soil around truffle-producing oak trees, and he subsequently
obtained large harvests of truffles. He received a prize
at the 1855 World's Fair in Paris.
These successful attempts were met with enthusiasm
in southern France. In the late 19th century, an epidemic
of phylloxera destroyed most of the vineyards in southern
France. Another epidemic destroyed most of the silkworms
in the area, rendering the fields of mulberry trees
useless. Large tracts of land were set free for the
cultivation of truffles and thousands of truffle-producing
trees were planted. Production reached peaks of hundreds
of tonnes at the end of the 19th century. In 1890 there
were 750 km² (185,000 acres) of truffle-producing
In the 20th century, with the growing industrialisation
of France and the subsequent rural exodus, many of these
truffle fields (champs truffiers or truffières)
returned to wilderness. The First World War also dealt
a serious blow to the French countryside, killing 20%
or more of the male working force. As a consequence,
newly acquired techniques of trufficulture were largely
lost. Between the two world wars, the truffle fields
planted in the 19th century stopped being productive.
After 1945 the production of truffles plummeted, and
the prices consequently rocketed.
In the last 30 years, new attempts for a mass production
of truffles have been made. Eighty percent of the truffles
now produced in France come from specially planted truffle-fields.
Production has yet to recover its 1900's peaks. The
countryside in southern France is largely depopulated,
with a lot of the lands in the hands of the descendants
of the farmers. These descendants live in towns and
cities and feel mostly unconcerned by the countryside.
Local farmers are also opposed to a return of mass production,
which would decrease the price of truffles. However,
prospects for a mass production are immense. It is currently
estimated that the world market could absorb 50 times
more truffles than France currently produces. There
are now truffle-growing areas in Spain, Sweden, New
Zealand and Australia.
The Tuber Aestivum summer truffle is harvested from
May until December, while two lesser-used truffles include
the Tuber Macrosporum black truffle and the Tuber Mesentericum
Soils for truffles
It is clear that T. mélanosporum can prosper
in certain types of chalky or lime soils, in a fairly
wide range, however.
mélanosporum is found in the limey gréseux
of Maestrich ( Ste Alvère-24 ), as on the Turonn
chalks (crétacé sup.-37), as in the recent
calcareous alluvions fluviatiles ( Carpentras ). Section
of a truffle-bearing soil.
Soil analyses on these different sites known to be
good producer show constant factors in physical characteristics,
structure, water retaining capacity balanced elements
( clay, lime, sand ), drainage capacity.
Among the chemical characteristics, it can be noticed
that there are slight variations of PH ( water ), of
C/N and of exchangeable CaO and a possibly of wide variation
in phosphorus, potassium, organic matter. If the physical
characteristics can changed little, the chemical attributes
can be compensated for easily.
Ecology of truffles
The life and death of the roots in the soil take part
in its permanent transformation. The living roots enter
the cycle of organic matter and help improve the fertility
of of the environment necessary for the development
of the fungus. The mésofauna will do its indispensable
work of chopping up, digestion, aeration and nutrition
where the mélanosporum will prosper.
Truffles belong to a group of edible subterranean
(mycorrhizal) fungi of the genus Tuber, class
Ascomycetes, and division Mycota.
Mycorrhizes are the organs of symbiose (symbiosis)
between the tree and the fungus The link between
the fungus and the roots is established from a
a intercellular network called the Hartig network.
The mycorrhizes emit colonising hyphes which pass
the infection on to to other root apices and,
replacing the absorbing hairs, will explore the
soil, looking for mineral elements. Mycorrhize
It is at the level of the mycorrhizes that the
nutritional exchanges of the symbiosis take place.
The tree gives sugar to the truffle (carbon hydrates)
resulting from photosynthesis, while the fungus
provides mineral salts (phosphorus) for the tree.
It helps the tree to support high calcium levels
and better manage its water supplies. If the hyphes
stay outside the cortical cells of the root they
are ectomycorhizes the case of the truffle Inside
they are endomycorhyzes.
These symbiotic organs are called mycorrhizes.
As soon as they are formed they emit colonising
hyphes which transmit the infection to other apex
roots; which propagate by the root cortex.
The Tuber melanosporum black truffle comes almost
exclusively from Europe, essentially France (45%
of production), Spain (35%), and Italy (20%).
Small productions are also found in Slovenia and
Croatia. In 1900, France produced around 1,000
metric tonnes (1,100 short tons) of Tuber melanosporum.
Production has considerably diminished in one
century, and nowadays production is usually around
20 metric tonnes (22 short tons) per year, with
peaks at 46 metric tonnes (50 short tons) in the
best years. 80% of the French production comes
from Southeast France: upper-Provence (départements
of Vaucluse and Alpes-de-Haute-Provence), part
of Dauphiné (département of Drôme),
and part of Languedoc (département of Gard);
20% of the production comes from southwest France:
Quercy (département of Lot) and Perigord.
The Tuber magnatum pico white truffle is mostly
found in northern and central Italy while the
Tuber Borchi, or whitish truffle, is found in
Tuscany, Romagna and the Marche.
Methods of culture
After having chosen the land, analysed the soil,
fixed the planting density according to richness
of the soil and the method to be used, a productive
variety of plant should be selected. Carefully
studying the milieu and associated vegetation
will give clues as to the closest truffle bearing
plants and certain physical characteristics of
the soil such as water retention. To be mistaken
in the choice of plants can be severely handicapping
for future production. When ordering the plants
a minimum of 3,5/5 of mycorrhization should be
required together with the appropriate proof.
If a high density system is chosen, planting in
less rational square formations should be avoided.
6m x 4 m, 6 m x 3 m, 5 m x 3 m are suitable for
infertile soils. North-South slopes are preferable.
After ploughing and use of tines according to
the depth of the soil, staking and must be carried
out. Planting must be carried out carefully, without
damaging the root balls. If the rootballs are
Melfert ®, make slight cuts in the cellulose.
The plants should be planted one abed of fine
earth, and the holes filled in and beaten down
gently. Protection should be provided against
1st year. Alternate cultivate with disc-harrows
and tines (15cm deep) close to the rows. Hoe around
the plants. There is an implement (the Cultimatic)
for keeping the rows clean.
2nd year, same requirements, but staying 30cm
from the rows.
3rd year, continue but reduce the depth to 10cm
and increasing the distance to 70 cm. The rabbit
guard should be removed but an electric fence
should be put around the plantation. If deer are
plentiful, use four wires at 20, 50, 110 et 180
cm. The first brûlés will be visible.
4th year, Only one cultivation with vibrating
tines at 6/8 cm in March. Weed growth can be dealt
with at an early stage by Round-Up (1litre/ha)
+ L I 700.
5th year and following: First truffles, one harrowing
per year in March on dry ground.
With a slightly lower density (6 m x 6 m for example).
Same planting precautions using Tubex. The orientation
is less important but plant with the slope. 1st
year Alternate use of discs and harrows with the
slope to 1,5 to 2 metres on each side of the rows.
Roll the middle and mow often.
2nd year, stop all mechanical cultivation, keep
clean with Round-up 1m each side of the rows.
Leave the protection while the trees cannot take
close weedkilling and mow.
3rd year and following: stop weedkilling and