How to Produce Kattha from Kaju Ka Chilka

If you work with cashew processing, you already know that kaju ka chilka – the thin brown skin on the kernel – usually leaves the factory as low‑value husk or fuel. [web:2][web:13]

This same material actually contains valuable catechin and tannins that can be converted into commercial‑grade Kattha for pan masala, mouth fresheners and herbal formulations. [web:5][web:7][web:16]

What Exactly Is Kaju Ka Chilka / Cashew Testa?

During cashew processing, raw cashew nuts are steamed or roasted and the shell is removed to get the white kernel. [web:12]

Around each kernel there is a thin brown layer known as cashew testa, cashew husk or kaju ka chilka, which can be separated in the peeling step and collected as a by‑product. [web:2][web:13]

From roughly 100 kg of edible cashew kernels, you can expect about 10–12 kg of clean testa, rich in catechin and tannins suitable for Kattha production. [web:5]

Process Overview – 5 Key Steps from Chilka to Kattha

1. Collection and cleaning of kaju ka chilka (cashew testa).
2. Hot water boiling and multi‑stage extraction.
3. Filtration and controlled concentration of the extract.
4. Slow crystallisation to form Kattha crystals.
5. Pressing, cutting, drying and tannin by‑product recovery.

Step 1 – Collection and Cleaning

First, you tie‑up with a shelling unit or your own cashew factory peeling section to collect uniform, food‑grade chilka with minimum shell pieces, dust or oil contamination. [web:2][web:13]

For a 1–2 tonne per day cashew plant, this stream is already available; you only need proper bins and a simple cleaning line to remove stones and heavy impurities. [file:1]

Step 2 – Hot Water Extraction (10–24 Hours)

The catechin and tannins inside kaju ka chilka need long contact with hot water to move into solution. [web:5][web:11]

One published process example uses 10 kg of dried cashew testa boiled with about 50 kg of water at 90–95 °C for 5–6 hours in a copper or stainless steel vessel, followed by two additional extractions with smaller water volumes. [web:5]

After each extraction, the liquid is drained and the residue is pressed, so that you get three combined dark brown extracts with maximum recovery. [web:5]

Step 3 – Filtration and Concentration

The mixed extract is passed through coarse and fine filtration – typically a filter cloth or plate filter – to remove suspended solids. [web:5]

Then it is concentrated in an open pan, steam‑jacketed kettle or vacuum evaporator until it reaches about 20 °Bé (roughly 1.175–1.25 specific gravity), which is suitable for controlled crystallisation. [web:5]

Step 4 – Crystallisation to Kattha

The concentrated extract is transferred to clean, food‑grade containers and allowed to cool and stand undisturbed for 5–10 days at ambient temperature. [web:5]

During this time, brownish‑white Kattha crystals slowly form. They are separated from the mother liquor by filtration or pressing to obtain a semi‑solid Kattha cake. [web:5][web:7]

This cake is cut into blocks or tablets and dried at 50–60 °C followed by shade drying to reach the required final moisture. [web:5][web:7]

Step 5 – Tannin By‑Product Recovery

The remaining mother liquor is still rich in tannins and can be further concentrated to produce a tannin cake for leather tanning, natural dyes or agro‑inputs. [web:5][web:11]

In this way, ek hi raw material – kaju ka chilka – se you can obtain two value‑added products: Kattha and tannin extract. [web:5][web:7]

Quality Parameters to Watch

• Catechin content (%): higher percentage means more premium Kattha grade. [web:5][web:7]
• Colour: brownish‑white to light brown with a uniform shade and minimal black spots. [web:7]
• Moisture: controlled drying can give 12–18 months shelf life in proper packing. [web:7]
• Contaminants: shell oil, dust, microbes and heavy metals should stay within food limits. [web:11]

Plant Design – How S.S. Fabrication Can Help

Whether you run a 500 kg/day or 5 tonne/day cashew plant, S.S. Fabrication can design a Kattha extraction module that integrates with your existing boiler, utilities and space. [file:1]

The focus is always on recovery, fuel efficiency and operator safety, so that kam investment se zyada output and consistent Kattha quality can be achieved. [file:1][web:5]