Botany and origin of the hazelnut tree
The hazelnut (Corylus avellana) is one of the oldest plants in human diet. Charred hazelnut shells dating back 9,000 years have been found across northern Europe, from Scotland to Sweden, including a famous Mesolithic site on the Scottish island of Colonsay where archaeologists uncovered a roasting pit holding hundreds of thousands of charred hazelnut shells. Stone Age humans organized seasonal harvesting and processing on an industrial scale.
The hazel is a small to medium shrub or tree (3-8 meters), with broad oval leaves and male catkins that open in late winter. The female flowers, tiny crimson stars, are wind-pollinated and develop into nuts encased in a leafy husk. Each cluster carries 1-4 nuts. The shell is thin, smooth, and easy to crack, one reason the hazelnut spread so easily through prehistoric Europe.
The Latin name avellana comes from the town of Avella in the Campania region of southern Italy, where the Romans cultivated hazelnut commercially. The English name "filbert" comes from St. Philibert's Day (August 22), which roughly coincides with the start of the European hazelnut harvest. The same nut, three names: hazelnut, filbert, cobnut.
The hazelnut is one of the few nuts that grows on a bush, not a tree. That accident of botany has shaped everything about the industry: hand-harvest dependence, slow modernization, and Turkey's lock on global supply.
Growing regions: Turkey, Italy, and Oregon
The hazelnut market is the most geographically concentrated of any major tree nut. Turkey produces roughly 70% of global supply, and within Turkey, production is concentrated in a single 500km strip along the Black Sea coast (Ordu, Giresun, Trabzon). The mild humid climate, steep slopes, and 100-year-old terraced hazelnut groves create conditions that simply can't be replicated.
Italy is the second producer, concentrated in Piedmont (the "Tonda Gentile" variety, used in Nutella and the famous Italian chocolate-hazelnut industry), Campania, and Lazio. Italian volume is smaller but commands a premium for variety, processing standards, and cultural cachet.
Oregon is the American outlier. The Willamette Valley has roughly 85,000 acres of hazelnut, producing 99% of U.S. hazelnut. The industry has grown sharply in the last decade as new disease-resistant varieties from Oregon State University replaced the older Barcelona variety. Oregon's quality is consistently high, but volume is small relative to Turkey.
Ferrero, the Italian company behind Nutella, Ferrero Rocher, and Kinder, buys approximately 25-30% of the world's hazelnut crop. That single buyer's hedging and inventory decisions shape global hazelnut prices. When Ferrero builds inventory, prices firm. When they pause, prices soften. No other tree nut market is this concentrated on the demand side.
The varieties that run the trade
Grown in the Giresun region of Turkey's Black Sea coast. Round, regular kernel with thin skin and intense aromatic flavor. The benchmark Turkish hazelnut. Used in the highest grades of confectionery worldwide. Premium pricing.
Mixed varieties from the broader Black Sea region (Ordu, Trabzon). Slightly elongated kernel, more variable than Tombul, used across the industrial scale: chocolate, hazelnut paste, oil, flour. The grade most exporters call simply "Turkish hazelnut."
The Piedmont variety. PDO (Protected Designation of Origin) certified. Distinctive flat-round shape, excellent thin-skin removal after roasting, and refined aromatic profile. The variety Ferrero originally built Nutella around. Commands a substantial premium over Turkish.
Developed at Oregon State University in the 2000s, designed for resistance to Eastern Filbert Blight that had devastated the older Barcelona variety. Large kernels, consistent quality, mechanized harvesting compatible. Most-planted varieties in Oregon today.
Nutrition and the vitamin E profile
Hazelnut is the highest vitamin E source of any common tree nut. A 100g serving delivers about 15mg of alpha-tocopherol, exceeding even almond. It's also rich in folate, copper, manganese, and oleic acid (the same monounsaturated fat that defines olive oil).
The fat profile is unusually clean: 75% monounsaturated, 13% polyunsaturated, only 5% saturated. The hazelnut's reputation for cardiovascular benefits comes from this profile, plus the high vitamin E content. Mediterranean Diet research consistently includes hazelnut as a recommended daily nut.
Processing and forms
Hazelnut is sold in five primary forms, each with different markets:
| Form | Description | Main use |
|---|---|---|
| In-shell | Whole nut in natural shell | Holiday season, gifts |
| Natural kernels | Whole kernels with skin (testa) | Retail, snacks, baking |
| Blanched kernels | Skin removed (post-roasting) | Premium chocolate, confectionery |
| Roasted kernels | Dry-roasted whole or chopped | Snacks, ice cream inclusions |
| Hazelnut paste / praline | Ground roasted kernels | Industrial confectionery (Nutella, gianduja) |
The Turkish processing flow: hand-harvest in August-September, sun-dry in-shell for 3-4 weeks, mechanical shelling, sorting by size and color, then either bagged for export as natural kernels or further processed locally for paste and oil. Most premium-grade hazelnuts ship as blanched kernels for European chocolate makers.
Hazelnut is particularly vulnerable to aflatoxin contamination if drying is delayed or moisture rises above 7% during storage. EU regulations on hazelnut aflatoxin limits are among the strictest in the food trade. Reliable suppliers run lab testing on every batch before shipment.
The buyer's guide
Hazelnut buying decisions hinge on one question: are you using it as the star, or as an ingredient? The answer determines origin and grade.
Star ingredient (snacks, premium chocolate, gourmet): Turkish Tombul or Italian Tonda Gentile. The shape, skin removal, and flavor intensity matter. Pay the premium.
Industrial inclusion (paste, oil, flour, bulk confectionery): standard Turkish Levant or Oregon. The cost difference is meaningful at scale, and the flavor difference disappears once it's processed into a paste or filling.
For storage: hazelnut is more stable than walnut or pine nut, but less stable than almond. Refrigerate shelled hazelnut after opening. Use within 4-6 months. Freezer: up to a year.
Hazelnut is one of the eight major food allergens. Cross-reactivity is common with birch pollen (oral allergy syndrome) and with other tree nuts. Hazelnut allergy is one of the most prevalent tree-nut allergies in Northern Europe specifically. Anyone with tree-nut allergy should be tested specifically for hazelnut.
The hazelnut market is the most concentrated in the trade: 70% from one country, 30% bought by one company. Understanding that is half of understanding the price.
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