Hazelnut

Ripe hazelnuts

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.^[1] 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.

Hazelnuts are used in confectionery to make praline, and also used in combination with chocolate for chocolate truffles and products such as Nutella and Frangelico liqueur. Hazelnut oil, pressed from hazelnuts, is strongly flavoured and used as a cooking oil. Turkey is the world's largest producer of hazelnuts.

Hazelnuts are rich in protein, monounsaturated fat, vitamin E, manganese, and numerous other essential nutrients.

Historical cultivation

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 nuts were radiocarbon dated to 7720+/-110BP, which calibrates to circa 7000 BC. Similar sites in Britain are known only at Farnham in Surrey and Cass ny Hawin on the Isle of Man.^[2][3] See also Sruwaddacon Bay, Kilcommon, Erris, County Mayo, Ireland.

This discovery gives an insight into communal activity and planning in the period. The nuts were harvested in a single year, and pollen analysis suggests the hazel trees were all cut down at the same time.^[3] The scale of the activity, unparalleled elsewhere in Scotland, and the lack of large game on the island, suggest the possibility that Colonsay contained a community with a largely vegetarian diet for the time they spent on the island. The pit was originally on a beach close to the shore, and was associated with two smaller, stone-lined pits whose function remains obscure, a hearth, and a second cluster of pits.^[2]

Because hazelnuts do not generally need to be toasted, indeed Kentish cobnuts are still traditionally sold fresh; ostensibly this was done to make them more digestible for children. Toasting the nuts was thought to increase how long they would keep, and they have historically been a useful food for mariners because they keep well.

Hazel has been grown historically in coppices for use in wattle and daub buildings, and in hedges. The Romans cultivated hazelnuts, including in Britain, although no evidence indicates they spread specific cultivars. Cultivated varieties have been grown since at least the 16th century, with a great increase in varieties during the 1800s. In particular, the first really widespread cultivar, the 'Kentish Cobnut', was introduced in 1830.

The traditional method to increase nut production is called 'brutting', which involves prompting more of the trees' energy to go into flower bud production, by snapping but not breaking off the tips of the new year's shoots' six or seven leaf groups from the join with the trunk or branch, at the end of the growing season. The traditional term for an area of cultivated hazelnuts is a plat.

Modern cultivation

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. The name "hazelnut" applies to the nuts of any of the species of the genus Corylus. This hazelnut, 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 has a bitter flavour and is sometimes removed before cooking.

Top ten countries with the largest production of hazelnuts in 2012[4] (thousand tonnes)
Rank	Country	Production	Rank	Country	Production
1	Turkey	660	6	China	23
2	Italy	85	7	Iran	21
3	United States	30	8	Spain	14
4	Azerbaijan	29	9	France	8
5	Georgia	24	10	Poland	4

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. Turkey is the largest producer of hazelnuts in the world with about 75% of worldwide production.^[5]

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.^[5] Ferrero SpA, the producers of Nutella and Ferrero Rocher, consumes 25% of the global supply.^[6]

In North America: in the United States, hazelnut production is concentrated in Oregon; they are also grown extensively just to the north, in the Fraser Valley of British Columbia, Canada. In 1996, the in-shell production in Oregon was about 18,100 tonnes (19,900 short tons), compared to 91 tonnes (100 short tons) in Washington. The hazelnut is growing in popularity in the U.S., the Hazelnut Marketing Board was established in 1949 by the Federal Hazelnut Marketing Order section 982.

Hazelnuts are also found in the Pangi Valley of Chamba district in India, where they are known as thangi.

Cultivars

Turkish Corylus colurna

The many cultivars of the hazel include: 'Barcelona', 'Butler', 'Casina', 'Clark', 'Cosford', 'Daviana', 'Delle Langhe', 'England', 'Ennis', 'Fillbert', 'Halls Giant', 'Jemtegaard', 'Kent Cob', 'Lewis', 'Tokolyi', 'Tonda Gentile', 'Tonda di Giffoni', 'Tonda Romana', 'Wanliss Pride', and 'Willamette'.^[7] Some of these are grown for specific qualities of the nut; these qualities include large nut size and early- and late-fruiting cultivars, whereas others are grown as pollinators. The majority of commercial hazelnuts are propagated from root sprouts.^[7] Some cultivars are of hybrid origin between common hazel and filbert.^[8] One cultivar grown in Washington state, the 'DuChilly', has an elongated appearance, a thinner and less bitter skin, and a distinctly sweeter flavor than other varieties.^[9][10]

Harvesting

Hazelnuts are harvested annually in mid-autumn. As autumn comes to a close, the trees drop their nuts and leaves. Most commercial growers wait for the nuts to drop on their own, rather than use equipment to shake them from the tree.

Four primary pieces of equipment are used in commercial harvesting: the sweeper, the harvester, the nut cart and the forklift. The sweeper moves the nuts into the center of the rows, the harvester lifts and separates the nuts from any debris (i.e. twigs and leaves), the nut cart holds the nuts picked up by the harvester, and the forklift brings a tote to offload the nuts from the nut cart and then stacks the totes to be shipped to the processor (nut dryer). The sweeper is a low-to-the-ground machine that makes two passes in each tree row. It has a 2 m (6 ft 7 in) belt attached to the front that rotates to sweep leaves, nuts, and small twigs from left to right, depositing the material in the row's center as it drives forward. On the rear of the sweeper is a powerful blower to blow material left into the adjacent row with air speeds up to 90 m/s (300 ft/s). Careful grooming during the year and patient blowing at harvest can eliminate the need for hand raking around the trunk of the tree, where nuts can accumulate. The sweeper prepares a single center row of nuts narrow enough for the harvesting tractor to drive over without driving on the center row. It is best to only sweep a few rows ahead of the harvesters at any given time, to prevent the tractor that drives the harvester from crushing the nuts that may still be falling from the trees. Hazelnut orchards may be harvested up to three times during the harvest season, depending on the quantity of nuts in the trees and the rate of nut drop as a result of weather.^[11]

A sweeper makes its first pass as it centralizes the material on the orchard floor

The harvester is a slow-moving machine pushed by a tractor, which lifts the material off the ground and separates the nuts from the leaves, empty husks, and twigs. As the harvester drives over the rows, a rotating cylinder with hundreds of tines rakes the material onto a belt. The belt takes the material over a blower and under a powerful vacuum that sucks the lightweight soil and leaves from the nuts, and discharges it into the orchard. The remaining nuts are conveyed into a nut cart pulled behind the harvester. Once a tote is filled with nuts, the forklift hauls away the full totes and bring empties back to the harvester to maximize the harvester's time.

Two different timing strategies are used for collecting the fallen nuts. The first is to harvest early when about half of the nuts have fallen. With less material on the ground, the harvester can work faster with less chance of a breakdown. The second option is to wait for all the nuts to fall before harvesting. Though the first option is considered the better of the two,^[12] two or three passes do take more time to complete than one. Weather must also be a consideration. Rain inhibits harvest and should a farmer wait for all the nuts to fall after a rainy season, it becomes much more difficult to harvest. Pickup also varies with how many acres are being farmed and the number of sweepers, harvesters, nut carts, and forklifts available.

A dry orchard can be dusty, so equipment operators should wear breathing protection. Conversely, if it is too wet, mud cakes in the machinery and moisture weighs down the material, making it impossible for the equipment to function without picking up large quantities of mud.

Nutrients

Hazelnuts or filberts, raw

Nutritional value per 100 g
Energy	2,629 kJ (628 kcal)
Carbohydrates	16.70 g
Sugars	4.34 g
Dietary fiber	9.7 g
Fat	60.75 g
Protein	14.95 g
Vitamins
Vitamin A equiv. beta-carotene lutein zeaxanthin	(0%) 1 μg (0%) 11 μg 92 μg
Thiamine (B1)	(56%) 0.643 mg
Riboflavin (B2)	(9%) 0.113 mg
Niacin (B3)	(12%) 1.8 mg
Pantothenic acid (B5)	(18%) 0.918 mg
Vitamin B6	(43%) 0.563 mg
Folate (B9)	(28%) 113 μg
Vitamin C	(8%) 6.3 mg
Vitamin E	(100%) 15.03 mg
Vitamin K	(14%) 14.2 μg
Minerals
Calcium	(11%) 114 mg
Iron	(36%) 4.7 mg
Magnesium	(46%) 163 mg
Manganese	(294%) 6.175 mg
Phosphorus	(41%) 290 mg
Potassium	(14%) 680 mg
Sodium	(0%) 0 mg
Zinc	(26%) 2.45 mg
Other constituents
Water	5.31 g
Link to complete USDA Database entry
Units μg = micrograms • mg = milligrams IU = International units
Percentages are roughly approximated using US recommendations for adults. Source: USDA Nutrient Database

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 (see table). Particularly in high amounts are protein, dietary fiber, vitamin E, thiamin, phosphorus, manganese, and magnesium, all exceeding 30% DV (table). 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).^[13]

Edible uses

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.^[14]

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.

See also

• Filbertone, the principal flavor compound of hazelnuts
• List of hazelnut diseases
• The Hazel-nut Child

References

External links

Wikimedia Commons has media related to Corylus avellana.

• The dictionary definition of hazelnut at Wiktionary