PROCESS

Welcome to Sun Thermo Process

From Raw Nut to Refined Delight

At our cashew manufacturing unit in Tiruvannamalai, each cashew nut undergoes a careful, step-by-step transformation — guided by skilled hands, modern equipment, and a deep commitment to quality. Our process blends traditional expertise with hygienic, sustainable practices, ensuring that every kernel meets the highest standards from start to finish

PROCESS

1. BOILING

Purpose: Soften the outer shell for easier removal

Our process begins with steam boiling the raw cashew nuts. This critical step softens the tough outer shell, loosens the kernel inside, and helps maintain the nut's natural flavor and nutrients. By using clean, high-pressure steam instead of open fire roasting, we ensure a safer, cleaner, and more environmentally friendly process. The steamed nuts are then cooled and prepped for the next stage.

2. Shelling

Purpose: Extract the kernel without breakage

Once cooled, the cashews move to the shelling section, where the outer shell is carefully cracked. Our experienced team, supported by precision equipment, removes the shells with utmost care to preserve the kernel's shape and quality. Since the kernel is fragile at this stage, accuracy is vital — and our workers' expertise plays a key role.

3. Borma (Hot Air Drying)

Purpose: Reduce moisture and increase the peelability of kernels

The shelled cashew kernels still contain moisture and are raw in nature. To stabilize them and prepare them for peeling, the kernels are placed in Borma dryers — specialized hot air chambers that gently dry the nuts over several hours(generally between 8-10 hours) . This controlled heat drying helps maintain the kernel's natural texture, reduces spoilage, and gives them a light golden hue.

4. Humidification

Purpose: Make kernels flexible for easy peeling

After drying, the kernels are often brittle. To prevent breakage during peeling, they are transferred to a humidification room — a space with regulated humidity and temperature. This conditioning softens the thin skin (testa) covering the kernel, making it easier to peel while maintaining the nut’s integrity.

5. Peeling

Purpose: Remove the outer skin to reveal the clean kernel

Next, the kernels go through peeling, here the thin, reddish-brown skin is removed using gentle mechanical methods. Here in STP we use batch type peeling machines with technically strong team to overlook. This stage requires a carefull and technical approach to ensure the nut underneath remains undamaged. What emerges is the clean, ivory-colored cashew kernel ready for grading.

6. Color Sorting

Purpose: Ensure only uniform, high-quality kernels move forward

To maintain consistency and visual appeal, the peeled kernels are passed through color sorting machines. These machines use optical sensors to detect and reject any discolored, defective, or damaged kernels. Only the cleanest, most uniform nuts proceed to the next step, ensuring top-tier quality in every batch. Here in STP we use belt type sorters for wholes kernel to reduce breakage as much as possible and vertical sorters for broken kernels. All programs are preset and predetermined according to the orgins and specifications.

7. Grading and Upgradation

Purpose: Categorize kernels by size, shape, and quality

Cashews come in various sizes and shapes, and each has its own market demand. In this stage, we grade the kernels according to internationally recognized standards — such as W180, W210, W240, W320, and W450 — where the "W" stands for “White Whole”. Broken pieces are also sorted into categories like splits, butts, baby bits, etc. We also conduct quality upgradation to separate customized premium-grade kernels according to customer preference for export or specialty packing or local sales.

8. Packing

Purpose: Preserve freshness, flavor, and hygiene

Finally, the graded cashews are packed under hygienic conditions using equipments such as seivers,aspirators,conveyors,metal detectors, vacuum sealed pouches or nitrogen-flushed buckets etc. These packaging methods protect the kernels from moisture, oxidation, and contamination — preserving freshness for months(approx. 6 months). Each package is carefully labeled and batch-coded, ready to reach domestic and international markets.