Thursday, September 1, 2016


I remember getting fresh hazelnuts in the summer months and eating them right out of the paper bag the street vendor or the green grocer provided. Thus, I decided to be on the lookout for them this summer and finally, towards the end of July, I found a green grocer displaying some in front of his store in our neighborhood in Istanbul.

You can bite into fresh hazelnuts and easily break their shells with your teeth. They are oh so sweet, moist and meaty.

Now, after having rejoiced about my memories of eating fresh hazelnuts, I need to take a pause here so that I can explain my misconception about them; these are in fact a poorer quality of hazelnuts not worthy of commercial exploit which are therefore consumed only as appetizers while they are fresh. I am aghast!  I only found out about this distinction while writing this post and there will be more about it further down.

Ordinarily, hazelnuts ripen in August. They are harvested by shaking the nuts off the branches and gathering them from the ground by hand, or picking them directly off the tree.

Fresh hazelnuts are sometimes sold in their green sheaths or involucre. Often the vendors un-sheath the nuts before presenting them to the customers.


The shape and structure of the involucre, and also whether the plant grows into a tree or a shrub are important in the identification of the different species of hazel.

The first three of the following examples of hazelnuts categorized according to their involucre, grow in Turkey:
• Nut surrounded by a soft, leafy involucre, multiple-stemmed, suckering shrubs to 12 m tall.
         Involucre short, about the same length as the nut
            -Corylus avellana: Common hazel, Europe and western Asia.
         Involucre long, twice the length of the nut or more, forming a 'beak'
            -Corylus maxima: Filbert, southeastern Europe and southwest Asia
• Nut surrounded by a stiff, spiny involucre, single-stemmed trees to 20–35 m tall.
         Involucre moderately spiny and also with glandular hairs
            -Corylus colurna: Turkish hazel, southeastern Europe and Asia Minor
         Involucre densely spiny, resembling a chestnut burr
            -Corylus ferox: Himalayan hazel

Also, when we look into the characteristics of culinary nuts-dry, edible fruits or seeds that usually have a high fat content-we learn that hazelnuts are placed under the category labeled ‘true nuts’ or ‘botanical nuts’. The other three culinary nut categories are 'drupes' (e.g. almonds), 'gymnosperm seeds' (e.g. pine nuts) and 'angiosperm seeds' (e.g. peanuts).

Hazel trees (Corylus) are a genus of about 20 species, mainly deciduous trees and some large shrubs, that are all native to the temperate regions of the northern hemisphere. Hazelnut is their seed. The nuts of all species of Corylus are edible, however the species Corylus avellana is grown the most due to its higher production rate, and the fact that it has many cultivars.

The genus name Corylus comes from the Greek ‘krylos’, the word for hazelnut. “The scientific name avellana derives from the town of Avella in Italy, and was selected by Linnaeus from Leonhart Fuchs's De Historia Stirpium Commentarii Insignes (1542), where the species was described as ‘Avellana nux sylvestris’-‘wild nut of Avella’.” (

The genus is usually placed in the birch family Betulaceae. Wikipedia tells us that some botanists split the hazels with allied genera into a separate family Corylaceae.

Here are some interesting facts about the leaves, flowers and the nuts of the hazel plants.

Corylus avellana

Leaves: Hazels are deciduous. This means the leaves drop off in the fall and new leaves emerge in the spring. The leaves are rounded, about 6-12 cm long and 4-10 broad, with soft hairs on both sides, and they also have a coarsely doubly-serrate margin, meaning the leaves have forward pointing teeth (serrations), and each tooth has smaller serrations on it.

Flowers: Hazelnut trees are one of the few trees that bloom and pollinate in the late winter before the leaves emerge. The flowers on the hazelnut are monoecious, that is they have both male and female flowers on the same plant. The male flowers on a hazelnut are long, pale yellow catkins 5-12 cm long. The female hazelnut flowers are tiny red flowers that hide in the buds of the leaves and only their 1-3 mm long styles peak out. Wind carries the pollen from male catkins to a tiny red female flower, where it stays dormant until May when the nut begins to form.

Fruit/Nuts: The fruit of the hazelnut tree is actually the nut. Hazelnuts are cross pollinated. So, just as I think I’m getting a grasp of the facts about hazelnuts, I come across this matter of cross pollination. In the case of hazelnuts, cross pollination means two different varieties of trees are needed for the tree to produce nuts. About 6-10% of the trees in an orchard are pollinizer trees.

All varieties of hazelnuts require cross pollination in order to produce nuts, consequently, every planting requires two or more varieties. The cultivars are self-incompatible. There must be enough genetic difference between the pollen providing variety (male), and the main nut producer (female) for fertilization of the flower, and subsequent production of a nut, to occur. Thus pollinizer selection is very important.

I’m thinking, for the growers to keep track of which varieties of trees to keep and what genetic changes take place when the trees are pollinated by varieties of pollinizers, must require a resident geneticist on the farm.

The nuts grow in clusters and are about 1-2.5 cm long and 1-2 cm in diameter. Each nut has a protective involucre-husk that covers all or part of the nut, depending on the variety. The nuts are borne in tight clusters of 3-8 together, with the involucres fused at the base.

The nuts mature late August, early September. The developing nuts are green. When they mature, the nuts turn a chocolate brown or hazel color. The nut falls out of the husk-when ripe, about 7–8 months after pollination.

Two popular cultivars-variety of a plant that has been created or selected intentionally and maintained through cultivation-of hazelnuts are,
Corylus avellana var. avellana, distribution: Europe to Causasus
Corylus avellana var. pontica, distribution: N. Turkey, W. Trancaucasus

Hazelnut is one of the most important nut crops in the world and has its origins in central Anatolia or Asia Minor (alternate geographical names for the Asian territories of Turkey). Wild species are found in Anatolia which have provided the source for today's cultivated varieties.

Research into hazelnut production in Turkey indicates categorization according to shape.


Round Hazelnuts (Corylus Avellana):These are spherical hazelnuts with approximately the same length, width and thickness. They are high quality hazelnuts. They have high seed yields, as well as high fat and protein rates. All types that can be easily separated from skin and whitened belong to this group.

In this group, ‘Giresun Fat Hazelnut’ (Black Sea Region) is the highest quality type in the world.

Pointed Hazelnuts: This is the type with the length a little longer than the width and the thickness. These hazelnuts produce more scrap when breaking. Therefore, they are mostly marketed in shells. They have types called Sivri and İncekara.

Almond Hazelnuts: This is the type with the length much longer than the width and the thickness. These are generally big and showy but have low quality. They have two types called Circular Almond and Flat Almond. They are not suitable for shelling, therefore they are not dried and are mostly consumed fresh domestically.

Apparently, what I have been eating and loving when fresh are of this kind.

Turkish hazelnuts are yet again categorized into two groups for quality: Giresun and Levant.

Giresun Quality: In the Black Sea Region of Turkey, fat hazelnuts are grown in the entire province of Giresun and in several towns of the province of Trabzon. These are the highest quality hazelnuts in the world. They have the highest level of skin separation among the types.

Levant Quality: This is the common name given to all hazelnuts that are grown in regions other than the region of Giresun and specific towns of Trabzon. Called Levant Akçakoca, Levant Ordu, Levant Trabzon or Levant Samsun depending on the place they are grown, these hazelnuts have a lower level of fat than the Giresun quality hazelnuts but still a higher level of fat and a better taste than those grown in the other hazelnut growing countries.

The top countries producing hazelnuts are Turkey (70% of world production) followed by Italy (18% of world production), Spain, USA and Greece. Turkey is the number one world exporter.


Hazelnut is an important nut crop in the world. Besides protein, hazelnuts are a good source of vitamin E, calcium, magnesium and potassium.

Despite their limited commercial growing area, hazelnuts are the 4th largest tree nut crop in the world, behind cashews, almonds, and walnuts.

Not based on the amount of production necessarily but according to preference around the world, I would call almond the diamond of nuts. Next, the most appreciated nuts would be hazelnut, peanut, and walnut-the ruby, emerald and sapphire of nuts.  Duly, this would place all the other nuts in the category of semi-precious nuts/gem stones. Wouldn’t you agree?


  1. Hi Beste - we have nut groves here - of hazel trees ... and at home growing up we had trees - actually they were hedges ... but gave us nuts - I love the freshness of a newly picked nut. You've given us lots of interesting facts here ...

    I wrote about cob nuts and hazel nuts 7 years ago .. if you believe it: 10 months after I started blogging ...

    Plants and trees that give us foods are so interesting to see how they came about and where they came from originally ...

    Cheers and I do hope all is well with you - Hilary

  2. Hello Hilary, you and I, we both pay attention to nature and you have so much experience with plants.
    We're all doing great. Thank you for asking.
    Salut, Beste