From Wikipedia: “Hazelnut is the nut of the hazel and therefore includes any of the nuts deriving from species of the genus Corylus, especially the nuts of the species Corylus avellana. It is also known as cobnut or filbert nut according to species. A cob is roughly spherical to oval, about 15–25 mm (0.59–0.98 in) long and 10–15 mm (0.39–0.59 in) in diameter, with an outer fibrous husk surrounding a smooth shell. A filbert is more elongated, being about twice as long as its diameter. The nut falls out of the husk when ripe, about 7 to 8 months after pollination. The kernel of the seed is edible and used raw or roasted, or ground into a paste. The seed has a thin, dark brown skin, which is sometimes removed before cooking.”
“In 1995, evidence of large-scale Mesolithic nut processing, some 9,000 years old, was found in a midden pit on the island of Colonsay in Scotland. The evidence consists of a large, shallow pit full of the remains of hundreds of thousands of burned hazelnut shells. Hazelnuts have been found on other Mesolithic sites, but rarely in such quantities or concentrated in one pit.”
“The harvesting of hazelnuts is done either by hand or by manual or mechanical raking of fallen nuts. Common hazel is widely cultivated for its nuts, including in commercial orchards in Europe, Turkey, Iran, and the Caucasus. ...
Hazelnuts are produced in commercial quantities in Turkey, Azerbaijan, Italy, Greece, Cyprus, Georgia, Serbia, in the south of the Spanish region of Catalonia, in the UK county of Kent, and in the American states of Oregon and Washington, and south western British Columbia Canada.”
Largest export countries:
“The top producer of hazelnuts, by a large margin, is Turkey, specifically Giresun Province and Ordu. Turkish hazelnut production of 625,000 tonnes (689,000 short tons) accounts for around 75% of worldwide production. Ferrero SpA, the producers of Nutella and Ferrero Rocher, consumes 25% of the global supply.”
Italy is the second largest export country of hazelnuts.
“In a 100-gram serving, raw hazelnuts supply 2,630 kilojoules (628 kcal) and are a rich source (> 19% of the Daily Value, DV) of numerous essential nutrients. Particularly in high amounts are protein, dietary fiber, vitamin E, thiamin, phosphorus, manganese, and magnesium, all exceeding 30% DV. Several B vitamins have appreciable content. In lesser but still significant amounts (moderate content, 10-19% DV) are vitamin K, calcium, zinc, and potassium. Hazelnuts are a significant source of total fat, accounting for 93% DV in a 100-gram serving. The fat components are monounsaturated fat as oleic acid (75% of total), polyunsaturated fat mainly as linoleic acid (13% of total) and saturated fat, mainly as palmitic acid and stearic acid (together, 7% of total).”
“Hazelnuts are used in confectionery to make pralines, in chocolate for chocolate truffles, and in hazelnut paste products. In Austria, hazelnut paste is an ingredient for making tortes, such as Viennese hazelnut torte. In Kiev cake, hazelnut flour is used to flavor its meringue body, and crushed hazelnuts are sprinkled over its sides. Dacquoise, a French dessert cake, often contains a layer of hazelnut meringue. Hazelnuts are used in Turkish cuisine and Georgian cuisine; the snack churchkhela and sauce satsivi are used, often with walnuts. The nuts may be eaten when fresh or dried which produces a different flavor.”
“Hazelnut is a primary ingredient of the vodka-based liqueur, frangelico.
Over 2,000 tonnes (2,200 tons) are imported annually into Australia, mostly to supply the demand from the Cadbury-Schweppes company Ferrero.”