About the Istrian White Truffle
“Istrian White Truffle / Tartufo bianco d’Istria” refers to the fresh fruiting body of the underground fungus Tuber magnatum Picco, collected in the area of Istria County.
The aroma of the Istrian White Truffle / Tartufo bianco d’Istria is of medium to strong intensity, reminiscent of damp earth or a fungal smell, and may also have the aroma of ripe/fermented cheese, garlic, or wild garlic. Upon consumption, a very mild gaseous aroma is released, most resembling propane-butane. This combination of aromas makes the Istrian White Truffle / Tartufo bianco d’Istria highly distinctive; it quickly spreads through a room and can overpower other scents.
The taste of the Istrian White Truffle / Tartufo bianco d’Istria is earthy-fungal, can be reminiscent of ripe/fermented cheese, garlic, or wild garlic, and is very pleasant and mild at the beginning of the harvesting season, developing into an intense and strong flavor as the season progresses. The consistency of the Istrian White Truffle / Tartufo bianco d’Istria upon consumption is firm and dry; it crumbles into smaller pieces when bitten and is not soft or mushy.
The shape of the Istrian White Truffle / Tartufo bianco d’Istria is irregular, more or less oval, tuberous, sometimes flattened, with grooves and bumps that make it recognizable at first glance. The Istrian White Truffle / Tartufo bianco d’Istria is firm to the touch, with a feeling of freshness and fullness.
The size of the fruiting body can range from very small to 20 cm or more. Fruiting bodies of the Istrian White Truffle / Tartufo bianco d’Istria weigh at least 7 grams.
The peridium (outer layer) of the Istrian White Truffle / Tartufo bianco d’Istria is mostly smooth, but it is not uncommon for it to be rough and coarse, i.e., finely granulated to finely warty, depending on the micro-location conditions in which it matures. The color of the peridium is light brown to ocher or yellow, nuanced, and other color highlights (dots or similar) may appear. It can also be in shades of darker brown, or even delicate greenish hues.
The gleba (inner part) is streaked with more or less irregular, thin white veins (sterile hyphae) that are very characteristic of the Istrian White Truffle / Tartufo bianco d’Istria, and can appear marbled. The area between the sterile hyphae is light brown, with shades of white, and can also be darker brown, with hints of ocher or reddish color.
The product is marked with a label/sticker that can be affixed to the product or packaging, or by printing directly on the packaging. The label/sticker or direct print on the packaging features the Protected Designation of Origin symbol and the logo of the Istrian White Truffle / Tartufo bianco d’Istria, as well as the first and last name, or legal name, of the producer. Each individual producer may add other information (e.g., contact details, collection date, etc.), provided that such data serves the traceability and authenticity of the product.
The Istrian White Truffle / Tartufo bianco d’Istria may only be collected in the area of Istria County, exclusively within the administrative areas of the towns of Buje, Buzet, Pazin, and Labin, and the municipalities of Grožnjan, Oprtalj, Brtonigla, Vižinada, Motovun, Lupoglav, Cerovlje, Kaštelir-Labinci, Višnjan, Karojba, Tinjan, Sv. Petar u šumi, Gračišće, Pićan, Kršan, Žminj, Sveta Nedelja, Barban, and Raša, i.e., in the area of the river basins of the Mirna, Butoniga, Boljunčica, and Raša rivers, their tributaries, and surrounding hills.
The Istrian White Truffle / Tartufo bianco d’Istria grows in well-drained soils with a moderately alkaline pH reaction, high calcium carbonate content, and sufficient water throughout the year. The soils where the Istrian White Truffle / Tartufo bianco d’Istria is found are characterized by the absence of prolonged water stagnation and a loose soil consistency. Such conditions are only possible in river valleys and on hillside slopes where geomorphological processes renew the soil, resulting in an irregular distribution of soil particles due to frequent deposition of alluvial material or accumulation of soil particles transported down slopes by mass movements.
Production areas of the Istrian White Truffle / Tartufo bianco d’Istria are linked to the flysch area, specifically the Mirna, Butoniga, Boljunčica, and Raša rivers, their basins, and surrounding hills. The Mirna and Butoniga rivers and their tributaries geographically form the broader Motovun Forest area, while the Boljunčica and Raša rivers with their tributaries define the Čepićko Polje area. Although these two production areas are the most well-known, the discovery of large white truffle fruiting bodies is possible outside these areas, as long as conditions for mycelial and fruiting body development exist.
The habitat of the Istrian White Truffle / Tartufo bianco d’Istria is specific due to the mild Mediterranean climate of the area, with rainfall of about 1000 mm/year, an average air temperature of 11°C, low altitude, without the influence of snow and prolonged icy winds, relatively young soil that is still in the process of formation, and the specific actions of watercourses that constantly rejuvenate the soil surface, i.e., the development zone of the Istrian White Truffle / Tartufo bianco d’Istria fruiting bodies. The production soils for Istrian White Truffles / Tartufo bianco d’Istria are alkaline, with high calcium carbonate concentration, macroporous (allowing water and air flow), and with a microclimate defined by a short dry period.
The Istrian White Truffle / Tartufo bianco d’Istria is recognized for its durability, and if stored properly, it can retain its freshness significantly longer than other members of the genus Tuber.
Unlike other fungi belonging to the genus Tuber, the mycelium of the Istrian White Truffle / Tartufo bianco d’Istria develops not only in the superficial, humic soil layer but also in deeper, mineral soil layers where the development of edible fruiting bodies occurs from late August to the end of January.
Occurrences of the Istrian White Truffle / Tartufo bianco d’Istria in the Istrian peninsula are exclusively linked to natural habitats. The availability of water and soil aeration influence the development of the very characteristic peridium of the Istrian White Truffle / Tartufo bianco d’Istria, which is thinner than the peridium of black truffles. In other words, it does not need to be thick and warty to reduce evapotranspiration, as the fruiting bodies of the Istrian White Truffle / Tartufo bianco d’Istria have a constantly available sufficient amount of moisture.
The combination of the mild Mediterranean climate and soil composition enables the development of this precious fungus, the specific shape of its fruiting body, and the development of intense aromas.
For the development of the Istrian White Truffle / Tartufo bianco d’Istria mycelium, the presence of host plants belonging to the genera of oaks (Quercus spp.), hornbeams (Carpinus spp.), poplars (Populus spp.), and willows (Salix spp.) is required, while a specific soil composition is necessary for the development of the fruiting body.
Of the total area of inland waters (canals, watercourses, and standing waters) in Istria County (7.57 km2), the production zones of the Istrian White Truffle / Tartufo bianco d’Istria are linked to 6.77 km2 of water surfaces, or 89.4% of the total area of inland waters.
The combination of the specific climate of the Istrian peninsula, soil formation and its physical-chemical properties, and the action of rainwater and watercourses create the preconditions for the development of Istrian White Truffle / Tartufo bianco d’Istria fruiting bodies with unique aromas and characteristics.