Walnut Processing Plant & Machinery Solutions

The green outer hull is stripped from the freshly harvested nut and the in-shell walnuts are washed to remove hull residue, field soil and stones. Clean shells dry more evenly and carry less staining onto the kernel.

The washed nuts are dried in warm air until shell and kernel reach a stable storage condition. Drying holds off mould growth and loosens the kernel inside the shell ahead of cracking.

Dried nuts are graded into size bands so the cracking gap can be matched to each band, and the shell is then broken open. Sizing before cracking is what keeps whole halves intact instead of shattering them.

The cracked mixture is separated so that shell fragments, light dust and unfilled nuts are drawn away from the kernel. Air and density separation handle the bulk of this before any hand inspection.

Kernels are separated into halves, quarters and pieces, then sorted by colour, since walnut trade grades run from light through to amber. Optical and camera sorting take out shell fragments, shrivelled kernel and discoloured pieces.

Graded kernels pass metal and X-ray inspection, are weighed to pack size and filled into pouches or cartons. Walnut kernel is high in oil, so gas-flushed and sealed formats are commonly specified for export packs.