Cashew Kernels: From Raw Nut to Export Grade
The cashew kernel is the edible nut inside the shell. Getting it out whole, white and correctly graded is the entire job of a cashew processing line.
A cashew kernel is the edible seed released when the hard cashew shell is cracked and the brown testa skin is peeled away. Kernels are the value in cashew processing: they are graded by size and colour into export classes (W180–W450 and below) and priced accordingly. The whole processing line — grading, steaming, shelling, drying, peeling, grading and packing — exists to deliver as many whole, white, undamaged kernels as possible.
Everything upstream of the kernel is preparation and everything downstream is packaging. The kernel is the product, and almost every decision on a cashew line comes back to one question: how much of it arrives whole, white and correctly dried.
What a graded kernel actually is
Kernels are sorted by count — how many make up a pound — then by colour, then by whether they are whole. A W320 grade means 300 to 320 kernels per pound, roughly 660 to 706 per kilogram. Scorched grades carry the same counts at a lower price, and anything broken drops into butts, splits or pieces.
| Class | What it means | Where it goes |
|---|---|---|
| White whole (W180–W500) | Unbroken, uniform pale ivory, graded by count | Retail packs and premium export |
| Scorched whole (SW) | Unbroken, heat-discoloured, same counts as white | Value retail, food manufacture |
| Butts and splits (B, S) | Broken across the width or along the natural split | Bakery, confectionery, snack mixes |
| Pieces (LWP, SWP, BB) | Large white pieces down to baby bits | Ingredient trade, pastes, toppings |
Full counts on the <a href="/cashew-grades/">grades page</a>. A plant does not choose its grade mix — the mix is the result of how well every stage before grading was run.
Moisture is the specification that gets plants in trouble
Kernel moisture is checked three times on a well-run line, and the target is different each time. Out of borma drying kernels sit at 3–4% and are brittle. Humidification brings the surface back to 5–6% so the testa releases without shattering the kernel. At packing the finished kernel must be at 3–5%, because anything wetter grows mould in a sealed pack on a six-week sea voyage and anything drier breaks in handling.
A mould claim on a container arrives months after shipment, costs the value of the load, and is almost always traced to packing moisture rather than to anything that happened at sea. A moisture meter at the packing station is the cheapest insurance on the line.
How kernels are packed for export
| Format | Unit | Carton | Notes |
|---|---|---|---|
| Vacuum tin | 11.34 kg (25 lb) | 2 tins per carton, 22.68 kg | The traditional export standard. Nitrogen-flushed, robust in transit, reusable. |
| Vacuum pouch | 10 kg | 2 pouches per carton, 20 kg | Lighter and cheaper than tins, now the more common format. Needs careful handling. |
| Bulk carton | 25 kg | — | For onward processing, where shelf life is short and the buyer repacks. |
Both vacuum formats are packed with nitrogen flushing and metal detection in line. See <a href="/cashew-vacuum-packing-machine/">vacuum packing</a>.
What protects kernel quality
Uniform raw-nut grading
a calibration line before shelling, because a cutter set for one nut size destroys every other size that passes through it.
Steaming at 3–4 bar
20 to 25 minutes softens the shell so it cuts rather than shatters. Under-steamed shells grip the kernel; over-steamed kernels mark.
Gentle shelling
the shelling stage is where whole-kernel yield is won or lost. Target under 3% broken and under 5% uncut.
Drying, then re-wetting
borma drying makes the testa brittle; humidification makes the kernel survive having it removed. Skipping the second is the classic mistake.
Whole white kernels are worth several times more per kilogram than pieces. On a plant running 10 tonnes of RCN a shift, a few percentage points of breakage is a larger number than most equipment decisions — which is why yield of wholes, not throughput, is the figure to negotiate machinery on.
The geometry behind it
Where CNSL actually sits
A cashew is not a nut with a shell around it — it is a drupe, and the layer that matters commercially is the honeycomb mesocarp between the outer and inner shell walls. That honeycomb holds the CNSL. It is separated from the kernel at shelling, which is why the testa peeled off later contains none of it.
Cross-section, schematic. The commercial consequence is the one people get wrong: “husk” is used for both the shell and the testa, and only the shell yields CNSL.
Frequently asked questions
What is a cashew kernel?
How are cashew kernels graded?
What moisture should packed cashew kernels be at?
How are cashew kernels packed for export?
How many kernels come out of 100 kg of raw cashew nuts?
Related reading & machines
Cashew Grades Explained (W180 to W450)
What the W-number really means
Open →
Cashew Peeling Machine
High whole-kernel yield, dry-peeled
Open →
Cashew Grading & Sorting Machine
W180 to W450, sorted by size and colour
Open →Benefits of Cashew Nuts
Cashews are a nutrient-dense nut — a source of healthy fats, plant protein, magnesium, copper and antioxidants — which underpins steady global demand for kernels.
Open →Talk to a cashew engineer
Tell us your target capacity, grades and location — we’ll come back with a costed proposal.