Traditional Kerala Cashew Processing

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Kollam was once the cashew capital of the world. At its peak, over 800 processing units employed nearly 300,000 people in this one city on Kerala’s southern coast. Then the industry industrialised — mechanised steam processing, massive throughput, and costs that Kerala’s manual workforce could not match. Factories closed. Banks seized units. A generation of cashew craft nearly disappeared.

The processors who remained made a choice: follow the industrial model, or double down on what they knew. Pretty Nuts is one that stayed.

Two Ways to Process a Cashew

Before a cashew kernel reaches your hand, it must be separated from its shell — a shell lined with caustic oil that makes the process more demanding than it sounds. There are two broad methods for doing this.

Steam processing subjects the raw nut to pressurised steam, softening the shell so it can be cracked and removed mechanically at high speed. It is consistent, scalable, and leaves the kernel visually pristine: white, intact, and uniform. For bulk export graded by appearance, it is hard to argue against.

Drum roasting uses dry heat inside a rotating drum to loosen the shell, which is then cracked and removed by hand. It is slower, demands skilled judgement, and produces a kernel with a slightly darker colour and occasionally more breakage. What it also produces is a kernel with significantly lower residual moisture — and that is where the eating quality diverges.

Why Lower Moisture Means Better Crunch

A cashew kernel is roughly 5% water by weight after shelling. How much of that moisture remains when the nut reaches you determines everything about its texture. Steam processing retains more of it. Drum roasting drives more of it out — not through the final product roast, but through the initial processing itself, and then again through the borma stage that follows.

Lower moisture means a drier internal structure. A drier structure means the snap when you bite is sharper and the crunch lasts longer through the pack. Industrial processing optimises for a kernel that looks perfect. Traditional Kerala processing optimises for one that eats perfectly.

The Borma Stage: Kerala’s Quality Step

After shelling, freshly extracted kernels carry high moisture — typically 8 to 12% — which causes the thin inner skin, called the testa, to cling tightly to the kernel. Peel at this stage and the kernel tears. This is where the borma comes in.

The borma is a slow-drying chamber, heated indirectly using the cashew shells themselves as fuel, running at 70–100°C. Kernels spend time in the borma until their moisture drops to around 3–4%. At that level, the testa lifts cleanly, the kernel holds its shape through peeling, and the crispness that defines a good cashew is built in before any final roasting begins.

This step is not glamorous. It does not appear on packaging. But it is the difference between a kernel that stays crisp and one that softens in the pack within weeks.

Hand Grading: What a Machine Cannot Do

Kerala’s cashew workforce is overwhelmingly women — skilled specialists whose grading judgement has been passed down across generations. A machine can sort by size. It cannot judge the subtle difference in colour that separates a W240 from a scorched reject, or the fine cracks that predict a kernel will break in transit.

Pretty Nuts grades by hand. Every batch. It is the only way to deliver the consistent whole kernels that our packs are built on.

What This Means for the Nut You Buy

The cashews in a Pretty Nuts pack have been through a process that has not chased convenience at any stage: drum-roasted at the shell, borma-dried for clean peeling, hand-graded for quality, and drum-roasted again at the final stage with no oil added. The result is a kernel that is drier, crispier, and more honestly flavoured than anything a high-throughput line can produce.

We have processed cashews this way in Kollam’s Chandanathope belt since 2005. We are not going to stop now.

Frequently Asked Questions

What is traditional Kerala cashew processing?

Traditional Kerala cashew processing uses drum roasting to loosen the shell with dry heat, followed by the borma drying stage where freshly shelled kernels are slowly dried at 70–100°C to reach 3–4% moisture. Every step is done by hand. The result is a kernel with lower final moisture, more natural flavour, and a drier, crisper bite.

What is the borma stage in cashew processing?

The borma is a slow-drying chamber used after shelling. Freshly shelled kernels carry 8–12% moisture, which makes the inner skin stick tightly and difficult to peel cleanly. The borma reduces this to 3–4% using indirect heat fuelled by the cashew shells themselves. At this level the skin peels cleanly and the kernel achieves the crispness that defines a quality cashew.

Why does drum roasting produce crispier cashews than steam processing?

Steam processing retains more moisture in the kernel, producing a white, intact nut ideal for export grading by appearance. Drum roasting uses dry heat, which drives moisture out further, giving the nut a drier internal structure. Lower moisture equals more crunch. The tradeoff is a darker colour and occasional breakage — neither matters if you are buying the nut to eat.

Why did so many Kerala cashew factories close?

At its peak, Kollam had over 800 processing units employing close to 300,000 people. When global processing industrialised, the cost of Kerala’s manual, skilled workforce could not compete on price alone. Many units closed or were seized by banks. The processors who remained chose quality over scale — the drum-roasting craft that a machine cannot replicate.