The white summer truffle is also known as Saint-Jean truffle, and the most often used scientific name is Tuber aestivum Vittad. This species have been named more than once and MycoBank (11 Oct. 2015), alleged that Tuber aestivum Vittad., 1831 is an illegitimate name (MycoBank (11 Oct. 2015) and stated the valid name for this taxon is Tuber aestivum (Wulfen) Pers. 1801.
The skin is black or brownish, laced with some protruding pyramidal warts, resembling Tuber uncinatum. However the size and appearance of warts cannot be used as criteria for distinguishment between Tuber aestivum from Tuber uncinatum as they vary significantly in every specimen.
The pulp is beige to brown or gray, covered with dark white branched veins, becoming yellowish at maturity . Non-maturity is recognized by the white or clear flesh. As a result, the veins of these truffles are very little at sight. The qualifier of white truffle was given to these mushrooms due to the color they have when immature .
Aroma and taste
One can feel a note of hazelnut into their delicate and pleasant aroma of wild mushrooms. The taste is similar to but not as strong as the taste of the truffle of Burgundy, and especially that of Tuber melonosporum. The summer truffle is a preferred product to be served soon after its harvesting in the producing regions during the summer season.
The summer truffle develops between April and June, and is quite dependant on the quantity rainfall. It fructifies from June to the end of September. Тhere is a risk of drying the truffle up by the hot summer sun when harvested immature and picking it on the surface.
This truffle was discovered for the first time in Belgium in 1964 at Montagne-au-BuisNote.
It is widespread in Europe and around the Mediterranean . It is found in France, Italy, Tuscany, Umbria, Marche, Abruzzo (under the name ‘scorzone’), as well as in Wallonia since the mid 20th century, Germany , Greece, Morocco and Algeria. Its harvest per year reaches 150 tons.
Tuber aestivum chooses calcium-magnesium soils, containing fine and coarse granulations, well drained. Typical for this truffle is to fruit very close to the surface of the soil while growing in symbiosis with hazelnuts, oaks, beeches, etc.
In France this truffle is disrespected. It is often used to train dogs.
Relationship between Tuber aestivum and Tuber uncinatum(Truffles of Burgundy)
The white truffle of summer Tuber aestivum is very close to the truffle of Burgundy Tuber uncinatum and no difference was discovered by the molecular biology tests . However, the new Truffes Fraiches standard, established after an interprofessional agreement signing by the French federation of truffle growers in 1996 ( updated in 2006), determined these truffles as closely related but not identical. The differences were classed as follows:
► Different maturity dates:
• from 1 May to 31 September -T. Aestivum
• from 15 September to 31 January -T. uncinatum;
►The color of the pulp
• lighter color of the T. aestivum
• darker color of the T. uncinatum;
• weak flavor in the T. aestivum
• stronger in the T. uncinatum;
►Ornamentation of the ascospores with a reticulo-alveolar network
• little evolved on the white truffle of summer
• much more evolved on the truffle of Burgundy.