The filbert is a popular tree nut, widely recognized in commercial markets and prized for its rich, distinct flavor. Often used interchangeably with the name hazelnut, both terms describe the edible fruit of trees within the Corylus genus. The confusion over the nut’s identity stems from regional naming conventions and subtle botanical differences between cultivated varieties. Its popularity in confectionery and baking has secured its place in kitchens worldwide.
Defining the Filbert: Name and Species
Filbert is a common name applied to the nut of the Corylus genus, though it technically refers to a specific species known as Corylus maxima. This species is botanically distinct from the common hazel, or cobnut, which is Corylus avellana. The physical difference between the two lies in the involucre, the leafy husk that encases the developing nut.
The true filbert, C. maxima, is distinguished because its husk is long and tubular, completely covering the nut and extending past its tip. In contrast, the common hazelnut, C. avellana, has a shorter, fringed husk that only partially covers the nut. For commercial purposes, however, the term “filbert” is often used broadly for all cultivated hazelnuts, particularly in regions like Oregon in the United States.
Regarding the name’s origin, the most accepted theory traces “filbert” to Saint Philibert, whose feast day, August 20th, historically coincided with the time when the nuts were ripe for harvest in England. Another theory suggests the name is a corruption of the Old German term vollbart, meaning “full beard,” a direct reference to the long, fully enclosing husk of the C. maxima species.
Cultivation and Global Production
Hazelnut trees, which include filbert varieties, thrive in temperate climates, requiring well-drained soil and ample sunlight. The trees are monoecious, meaning they have both male and female flowers on the same plant, but they are often self-incompatible, requiring cross-pollination from a different variety to set fruit effectively. This necessitates careful planning in commercial orchards, where growers plant multiple cultivars together to ensure successful pollination by the wind.
Global production is highly concentrated, with a vast majority of the world’s commercial crop originating in Turkey. The country accounts for approximately 75% of worldwide production, largely centered around the Black Sea region. Italy is another major producer, known for its specific varieties like the ‘Tonda Gentile Trilobata’.
In the United States, the industry is concentrated in the Willamette Valley of Oregon, which benefits from the mild climate and rich volcanic soils of the Pacific Northwest. After the nuts mature and fall to the ground, they are harvested using specialized machinery that sweeps them up. They are then cleaned, dried to reduce moisture content, and prepared for shelling or distribution to market.
Distinct Culinary Characteristics
The filbert is prized in cooking for its intense, complex flavor profile, which deepens significantly when roasted. The raw nut has a sweet, mildly earthy taste with a creamy texture, a quality enhanced by its high oil content. Roasting the kernels brings out a rich, buttery note and creates a satisfying crunch that makes the nut highly desirable in sweet and savory applications.
The nut is a staple in European and American confectionery, most famously used to create gianduja, a sweet chocolate-hazelnut paste, and praline. Whole, chopped, or sliced filberts are incorporated into cookies, tarts, and pastries, where their texture provides a welcome contrast to softer ingredients. Beyond desserts, filbert oil is pressed from the nuts for use in gourmet cooking, and the ground meal can replace flour in gluten-free baking.