In-Shell Hazelnuts for Industry: Specifications & Crack-Out Ratios
In-shell hazelnuts are the starting point of the industrial cracking and kernel-processing value chain. Their quality, size, shell integrity and crack-out yield directly influence processing efficiency, kernel quality and the economics of hazelnut production. This guide outlines international standards, industrial grading systems, moisture requirements, defect tolerances and procurement considerations for professional buyers.
1. Why in-shell hazelnuts matter in industrial processing
Most hazelnuts grown worldwide begin their journey as in-shell products before being cracked, sorted, and transformed into formats such as raw kernels, roasted kernels, chopped pieces, meal, flour, paste or oil. The integrity and grading of the in-shell nut determines the yield, defect levels and commercial value of downstream products.
- Higher shell quality reduces mechanical breakage during cracking.
- Larger in-shell sizes typically produce larger kernel calibers.
- Moisture content directly affects crack-out ratios and storage stability.
2. Industrial sizing standards for in-shell hazelnuts
Türkiye uses internationally recognized in-shell grading standards based on nut diameter. Size consistency ensures predictable kernel output during cracking operations.
Common industrial size grades
- 18–20 mm · smaller sizes used for standard kernel production
- 20–22 mm · widely used size class for high-volume cracking lines
- 22–24 mm · premium size, higher kernel yields
- 24–26 mm · large, limited-availability size for premium markets
Size uniformity is critical: mixed sizes reduce cracking efficiency and increase mechanical defects.
3. Crack-out ratio: the most important industrial metric
The crack-out ratio (also called kernel yield) measures how much usable kernel is obtained from a given quantity of in-shell hazelnuts. It is one of the key pricing factors for industrial buyers.
Typical crack-out ranges in Turkish hazelnuts
- 40–43% · standard industrial crack-out
- 43–45% · good-quality lots, better kernel uniformity
- 45–47%+ · premium in-shell lots with high-value kernel potential
Crack-out levels vary by cultivar, orchard practices, drying process and shell thickness.
4. Shell integrity & moisture content
Shell hardness and moisture levels play an essential role in cracking efficiency, machine wear and kernel breakage rates.
Recommended moisture levels
- In-shell hazelnuts: 10–12% for safe storage and transport
- Kernels post-cracking: reduced to approx. 3–5%
Higher moisture causes mold risk and unstable cracking; too-low moisture increases breakage.
Shell integrity considerations
- Shells should be intact, free from cracks, holes or insect penetration.
- Dark shell discoloration can indicate improper drying or storage issues.
- Uniform thickness ensures predictable cracking performance.
5. Defect tolerances & quality parameters
Industrial buyers evaluate defects based on shell condition and the anticipated impact on kernel yield.
Typical defect categories
- Moldy nuts: unacceptable in food-grade supply
- Empty shells: reduce yield and affect price
- Worm-damaged nuts: must be minimized via orchard control
- Stained or dark shells: may indicate poor drying or excess humidity
Processors usually specify maximum defect tolerances in purchase contracts to stabilize kernel output forecasts.
6. Storage & transportation guidelines for in-shell hazelnuts
In-shell hazelnuts must be stored carefully to preserve crack-out performance and prevent mold.
- Store at cool, dry temperatures (≤ 12°C is ideal).
- Protect from humidity and condensation during shipment.
- Ventilated packaging (e.g., jute or mesh bags) is preferred for long storage.
- Avoid prolonged exposure to heat, which accelerates rancidity.
7. Procurement guidance for industrial buyers
Buyers should define essential parameters in the purchasing specification to ensure predictable performance on cracking lines.
- Size grade (e.g., 20–22 mm) and uniformity requirements
- Minimum acceptable crack-out ratio
- Maximum defect tolerances
- Moisture levels upon shipment
- Origin region and cultivar (Tombul, Foşa, Çakıldak)
Clear communication with suppliers ensures consistent kernel output for downstream processing.
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