Indonesia is one of the world’s leading producers of green coffee beans, with a long-standing tradition of cultivating both Arabica and Robusta coffee. But behind every export-ready bag of green beans is a rigorous, multi-stage processing and grading system that ensures quality, consistency, and buyer satisfaction.
1. Gravity Separator: Enhancing Bean Density and Consistency
One of the earliest steps in green bean processing is using a gravity separator machine. This equipment is crucial for density grading, which helps segregate coffee beans based on weight and internal quality.
How It Works:
- Beans are fed into the machine and vibrated across a tilted deck.
- A controlled airflow lifts lighter materials while heavier, denser beans remain closer to the deck.
- The output is separated into heavy (premium), medium, and light (defective or underdeveloped) fractions.
Why It Matters:
- Higher density beans generally roast better and produce superior flavor.
- Gravity separation eliminates unripe, hollow, or insect-damaged beans.
2. Sortex Machine: Optical Sorting for Defect-Free Coffee
The next step in refining coffee quality is done through an optical sorter, commonly referred to as a Sortex machine.
Function:
- Sortex uses high-resolution cameras and AI algorithms to detect color, shape, and texture defects.
- It effectively removes black beans, discolored beans, foreign materials, and broken beans.
- Ejected defective beans are removed via compressed air nozzles.
Advantages:
- Increases visual quality and consistency.
- Critical for meeting strict import standards, especially in specialty coffee markets.
- Helps eliminate aflatoxin risks associated with black or moldy beans.
3. Screening Machine: Size Grading for Uniform Roasting
Uniformity in bean size plays a vital role in roasting consistency. The screening machine, or sieve grader, is used to separate beans based on their screen size (usually measured in 1/64 inch increments).
How It Works:
- Beans are fed through vibrating sieves of varying mesh sizes.
- Each screen allows only beans of a certain size to pass through.
- Beans are categorized into screen sizes (e.g., screen 13 to 20).
Importance:
- Uniform size results in even roasting, avoiding under- or over-roasted beans.
- Many buyers request specific screen sizes for espresso, filter coffee, or premium blends.
4. Polished Machine: Final Touch for Appearance and Cleanliness
Although not always mandatory, coffee polishing machines are used to enhance the appearance of green coffee beans. It removes the silver skin (a thin layer of parchment) that may remain after hulling.
Benefits:
- Adds a shiny, clean look to the beans, making them more visually appealing.
- Reduces dust and microbial load.
- Often used for premium or specialty-grade coffee exports.
Why Quality Processing Matters
Buyers today expect more than just origin and variety—they demand traceable, clean, and well-sorted green beans that roast consistently and deliver the cup profile they are paying for. Using advanced processing equipment like gravity separators, Sortex machines, screening machines, and polishers ensures your coffee meets these expectations.
At Nusa Caffeine, we don’t just export coffee; we elevate Indonesian green beans to international standards.
Final Thoughts
Understanding the green coffee processing journey is essential for buyers, roasters, and enthusiasts alike. Each step—from density grading to polishing—is part of a meticulous effort to ensure only the best beans make it into your cup.
Whether you’re a green coffee importer, roastery, or specialty buyer, choosing a supplier who uses these machines shows a commitment to quality, consistency, and food safety.