How are Hazelnuts Processed Commercially

Hazelnuts being processed in an industrial machine

The journey of a hazelnut from tree to table is a meticulous process that requires precision and care at every stage. Proper processing of hazelnuts is crucial for maintaining their quality, preserving their flavor, and ensuring their safety for consumption. 

In this article, we will explore the detailed journey of the hazelnut, outlining the critical steps involved in its processing after being harvested. We will discuss the careful procedures and sophisticated techniques employed to transform freshly picked hazelnuts into the flavorful nuts, and their derived products, we know so well.

Pre-Processing: Preparing Hazelnuts for Shelling

Let’s start at the beginning of the hazelnut processing journey: the pre-processing stage. This is where harvested hazelnuts are prepared for shelling. This phase includes de-husking, cleaning, size sorting, and drying. These procedures ensure the nuts are in the right condition for the following processing stages. 

De-husking: Removing the outer husks

Hazelnuts inside their husks

The husk is the green outer cover that encloses the hazelnut shell. While it’s an effective natural protector for the nut, it’s unsuitable for consumption or further processing.

Many hazelnuts naturally shed their husks, but some may still have their outer husks attached. In that case, removal is facilitated through special machines. Some advanced harvesting machinery comes with built-in de-huskers capable of removing the husks while still green. However, it is generally preferable to dry nuts with their husks at the processing facility. This drying process simplifies de-husking, making husks easier to detach.

Once dried, hazelnuts are passed through a de-husking machine. This machine gently removes any remaining husks without damaging the shell.

Cleaning and size sorting

Cleaning the shell is crucial as it removes any dirt, debris, or small stones picked up during harvesting. This cleaning ensures that only clean, quality hazelnuts move to the next stage.

The cleaning process usually involves passing the de-husked hazelnuts through an air stream that removes unwanted particles.

Once cleaned, the hazelnuts are sorted by size. Sorting is an essential process as it helps maintain consistency in subsequent steps. Hazelnuts are run through a series of sieves or screens with varying mesh sizes that separate the nuts into different size groups.

Drying to ensure optimal moisture

Drying is pivotal in preparing hazelnuts for shelling and facilitates long-term storage by maintaining an optimal moisture level. Once dried to this level, hazelnuts can be stored in their shells for over a year without losing freshness or flavor.

Hazelnuts drying in an industrial machine

The moisture content in freshly harvested hazelnuts can vary significantly. Hazelnuts that are overly moist risk spoiling or growing mold, while those that are too dry may lead to higher breakage rates during the shelling process.

To avoid these issues, the drying process is carefully managed to reduce the moisture content in the hazelnuts to an ideal level, typically around 8-12%. However, the optimal moisture level can vary depending on the specific hazelnut variety and the intended final product.

Many facilities utilize specialized drying equipment that controls temperature and humidity to ensure even drying of the nuts. However, a more traditional method is still used in certain regions where hazelnuts are spread out on concrete floors and dried naturally under the sun.

Hazelnuts drying on a concrete floor

Optional Distribution: In-shell Hazelnuts for Retail

Some processing facilities may choose to distribute a portion of their hazelnuts after the drying stage, particularly to retailers. These in-shell hazelnuts appeal to consumers who enjoy the hands-on experience of cracking open the shells themselves.

Even though these hazelnuts bypass the remaining processing stages, quality control and attention to detail during the pre-processing phase ensure their high quality. In other words, the cleaning and drying processes make these hazelnuts safe and ready for consumption.

These in-shell hazelnuts are often sold in bulk to supermarkets, health food stores, and specialty shops.

Shelling Process

The shelling process is vital to transforming harvested hazelnuts into consumable products. This phase involves shell cracking and kernel separation.

Hazelnut kernels separated from broken shells

Specialized equipment designed for cracking hazelnut shells is employed during this stage. These machines are built to apply the right amount of pressure to break the shell without damaging the valuable kernel inside. 

This is a delicate operation that requires precision. The shells need to be cracked just enough to allow the kernel to be separated without unnecessary damage. The objective is to preserve as much of the kernel as possible in its whole form, which increases its value.

Separating Shell and Kernel

After the shells have been cracked, the kernels must be separated from the broken shell pieces. This is usually achieved using aspiration and mechanical sorting. Aspiration uses a stream of air to blow away the lighter shell fragments. The heavier kernels fall into a separate collection area. 

On the other hand, mechanical sorting utilizes sieves or similar mechanisms designed with openings that allow shell pieces to pass through while retaining the kernels.

Through these processes, the shelling stage results in clean, whole hazelnut kernels ready for the next stage of processing

Post-shelling Processing

After the shelling stage, the clean, whole kernels proceed to the post-shelling processing phase. These steps are meticulously designed to ensure hazelnut quality, safety, and flavor profile. This phase prepares them for their incorporation into various food products.


During sorting, hazelnuts are inspected for size, quality, and potential defects. Specialized sorting machines can swiftly process large quantities of hazelnuts. These machines categorize nuts based on size and eliminate damaged, discolored, or imperfect kernels.

In addition to mechanical sorting, some processing facilities incorporate manual inspection into their quality control process. Experienced workers visually inspect the hazelnuts for any flaws the machines may have missed.

The sorting process ensures that only the highest quality hazelnuts proceed to the next processing stages. This rigorous quality control step contributes to the reputation of hazelnuts as a premium food product.

Direct Packaging of Raw Hazelnuts

Following the sorting stage, not all hazelnuts proceed to further processing. A significant portion of these sorted and shell-free hazelnuts are packaged directly. These are the raw hazelnuts you may find in grocery stores or markets. 

These hazelnuts, preserved in their natural state, are ideal for consumers who prefer to roast or process them at home. They’re also an option for culinary professionals who desire raw ingredients for their specific recipes.

Blanching and roasting

Blanching and roasting are transformative steps in the hazelnut processing journey. These procedures enhance the nuts’ appearance, texture, and flavor.


A pile of hazelnuts after blanching

This process involves briefly boiling the hazelnuts and then rapidly cooling them, usually in cold water. This procedure loosens the thin, dark skin covering the hazelnut kernel, making it easy to remove. The result is lighter, smoother hazelnuts. Various machines are available for efficiently carrying out this process on a large scale. 

Furthermore, not all blanched hazelnuts undergo roasting. Some are packaged and distributed in blanched form. It’s important to note that blanched hazelnuts aren’t classified as “raw” due to the heat applied during the blanching process.


Following blanching, a considerable portion of the hazelnuts undergoes roasting to bring out their rich and nutty flavor. Additionally, this process produces a crunchy texture. The heat breaks down the hazelnut fats and proteins, causing the Maillard reaction. It’s what gives roasted hazelnuts their golden-brown color and intense aroma. 

Roasting is performed in specialized ovens or roasters, which evenly distribute heat for consistent results. Roasting temperature and time are carefully calibrated depending on the desired end product. Light roasting may be preferred for a subtle flavor, while a dark roast produces a more robust and intense taste.

Further processing

After roasting and blanching, a portion of the hazelnuts is subjected to further processing to cater to specific uses. The versatility of hazelnuts becomes very obvious, as they are transformed into various forms and products. The subsequent steps include chopping, slicing, grinding, and more complex processes such as paste and butter production and hazelnut oil extraction. Each of these procedures has its unique methods and equipment.

Chopping, slicing, and grinding

Each of these techniques has its purpose and contributes to the wide range of hazelnut products available on the market.

Chopping: It breaks hazelnuts into smaller pieces, ideal for topping salads and desserts or incorporating into baked goods for added crunch and flavor. Specialized chopping machines handle large volumes of hazelnuts, ensuring consistency.

Slicing: This creates thin, consistent hazelnut pieces, often used for decorative purposes on pastries, desserts, or as a garnish on dishes. The precision of slicing machines ensures uniformity.

Grinding: It transforms hazelnuts into a fine powder or meal, often used in baking, as a component in gluten-free flours, or as a base for hazelnut butter and pastes. Grinding machines need to be powerful and well-maintained to avoid overheating, which can affect flavor and quality.

A small pile of hazelnuts after grinding

Paste and butter production

There is a substantial market for hazelnut paste and butter in the confectionery and baking sectors, as well as in direct consumer sales.

Hazelnut paste: It involves grinding hazelnuts into an ultra-fine consistency until they release their natural oils, creating a smooth and spreadable paste.

Hazelnut butter: It’s made by further grinding hazelnut paste until it achieves a creamy and butter-like consistency.

In both processes, the quality of the end product heavily depends on the care taken in grinding the hazelnuts to the right consistency and maintaining optimal temperatures. Professional grinding machines and cooling systems are often employed to ensure the best possible product.

Hazelnut oil extraction

A jar of oil extracted from hazelnuts

Hazelnut oil extraction is a sophisticated process that extracts flavorful oils from hazelnuts. This oil is known for its rich, nutty flavor and is used in various culinary applications. Additionally, it is a popular ingredient in the cosmetics industry for skincare and hair care products.

The process involves grinding the hazelnuts into a fine meal and applying pressure to extract the oil. After extraction, the oil is filtered for purity. 

This delicate process requires precision and expertise to achieve the desired quality and flavor. It is a testament to the versatile nature of hazelnuts, showcasing their potential beyond their familiar form as a crunchy snack.

Hazelnut Packaging

As hazelnuts near the end of their processing journey, proper packaging is essential to maintain freshness, quality, and shelf life. These precautions ensure that hazelnuts reach consumers in their prime state, ready to be enjoyed in all their delectable glory.

Types of packaging materials

The packaging of hazelnuts is done using various materials. These packaging materials safeguard against external elements, such as moisture, light, and oxygen. These factors can compromise the freshness and flavor of hazelnuts.

Packaging materials for hazelnuts include:

Flexible Pouches: Versatile and lightweight, these packaging options provide a barrier against moisture and oxygen. Flexible pouches often feature resealable closures, which help maintain hazelnut freshness after opening the package.

Rigid Containers: Sturdy containers made of plastic or metal offer excellent protection for hazelnuts. They are particularly useful for larger quantities and provide durability and ease of handling during transportation and storage.

Vacuum-Sealed Bags: This type of packaging extends hazelnut shelf life by creating an oxygen-free environment. By removing air from the package, these bags minimize oxygen that can make hazelnuts go stale. 

Tins and Cans: Packaging hazelnuts in tins or cans offers robust protection against moisture, light, and air. These types of packaging are especially popular for roasted and flavored hazelnuts.”

These packaging materials play a vital role in preserving the quality and taste of hazelnuts. They ensure that hazelnuts maintain freshness and flavor until they reach the consumer.

Quality and Safety Standards

Hazelnut processing involves meeting strict quality and safety standards. These facilities ensure that all products meet rigorous criteria, from harvest to packaging.

Key factors include adherence to food safety standards. Examples include Hazard Analysis and Critical Control Points (HACCP), and Good Manufacturing Practices (GMP). These measures help identify and manage potential food production risks. That way, it ensures hazelnuts are processed and packaged safely and hygienically.

In addition to these safety protocols, many processing facilities seek to attain industry certifications like the Global Food Safety Initiative (GFSI). This globally recognized certification affirms that a facility meets high food safety and quality standards.

Such stringent practices and regulations ensure that consumers receive the highest quality hazelnuts.


Proper hazelnut processing after harvesting is a multi-step journey that involves precision and attention to detail at each stage. From de-husking and drying to roasting, grinding, and packaging, each phase plays a crucial role in bringing out the best in the humble hazelnut.

By understanding this process, we can truly appreciate the care and skill that goes into turning harvested hazelnuts into the delicious product we enjoy in many forms. It underscores the significance of proper processing techniques for producing high-quality hazelnut products.

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