Cashew Nuts

Between the outer and inner layers of the cashew shell sits cashew nut shell liquid, a caustic, blistering material related chemically to the irritants in poison ivy. It is why cashews are never sold in the shell for consumers to crack, why cashew processing is a specialised industry rather than a simple cracking operation, and why the raw nut and the kernel are two different articles of trade with two different customs lines and two different price series.

Removing it is a defined industrial process — the shell is treated to neutralise or drive off the liquid before the kernel is extracted, dried, and peeled of its inner skin. AgricultureID describes this at concept level only: the actual procedures involve heat, caustic material, and an occupational hazard, and they belong to technical processing guidance and to occupational-safety authorities, not to a reference encyclopedia.

Raw cashew nut is what most cashew-growing countries actually export. It moves in bulk — bags and containers of whole, dried, unprocessed nuts — and it is bought on attributes that predict how many kernels a processor will recover from it: nut count per unit weight, moisture, and above all outturn, the trade's term for the kernel yield a lot delivers. Outturn is estimated by cutting test samples, and it is the number the price is built on.

This structure has long meant that the value added by processing accrues in different countries from those that grow the crop — West Africa exporting raw nut to processors in South and Southeast Asia has been the classic pattern, though origin processing capacity has grown. It is a rare case of a commodity whose trade geography is dictated by a processing hazard.

The nuts are dried after harvest and traded on a moisture basis, and like other oil-bearing nuts they are vulnerable to mould in inadequately dried lots and to insect infestation in storage. Raw cashew nut is a resilient commodity by fresh-produce standards but an exacting one by the standards of the buyer estimating outturn.

Cashew kernels are graded on wholeness, colour, and size. Whole kernels command a substantial premium over pieces, and since kernels break during shelling and peeling, the proportion of wholes a processor recovers is the measure of the operation's quality. Colour grades run from white through scorched and darker categories, reflecting how much heat the kernel met during processing. Size is expressed as count per unit weight, as it is for other nuts.

• Broken and split kernels — reducing the premium whole-kernel fraction
• Scorched and discoloured kernels from processing heat
• Mould growth and mycotoxin risk in inadequately dried nuts
• Insect infestation in stored raw nut and kernels
• Immature, shrivelled, and spotted kernels
• Rancidity in kernels held warm or long

Kernels are oil-rich and go rancid in the same way as other tree nuts, so packaging under vacuum or in modified atmosphere is standard for export, and cold storage is used to protect quality. Kernel grade standards are jurisdictional and versioned, and international trade also runs on established contract grade descriptions.

Cashew kernels are eaten as snack nuts and used heavily in confectionery, bakery, and cooking, and increasingly in plant-based dairy alternatives. The shell liquid removed during processing is not discarded: it is recovered as an industrial feedstock for resins, brake linings, and coatings, making it a by-product with real value. The cashew apple, though far more abundant by weight than the nut, is highly perishable and is mostly used locally for juice and fermented drinks rather than traded.

• Food — kernels as snack nuts and as a confectionery, bakery, and culinary ingredient
• Food processing — kernel pieces and paste, including plant-based dairy alternatives
• Industrial — cashew nut shell liquid recovered for resins, friction materials, and coatings