Kernel sorting is the separation of shelled nut kernels by size, colour and integrity to remove shell fragments, discoloured pieces and damaged kernels, establishing the final grade delivered to buyers.
In trade practice
Processing lines combine flat and cylindrical sieves for size separation, gravity tables to remove low-density defective pieces, and optical sorters to reject discoloured or mouldy kernels. Shell fragment removal is critical because hard foreign matter poses a food safety risk and triggers rejection under EU official controls. QA teams take timed samples to verify that defect levels remain within specification. Results are recorded on grading sheets that accompany the lot certificate.
In a specification
A kernel specification states maximum permitted percentages of shell fragments, discoloured kernels and broken pieces by weight, with grade names tied to size ranges defined by sieve aperture.