Coffee Grades & Specs
How to read and understand Vietnamese green coffee export specifications. Learn about the TCVN grading system, defect limits, and screen sizes (S16/S18) used in international trade.
The TCVN Standard
Vietnamese coffee is graded according to the national standard TCVN 4193 (currently TCVN 4193:2014). This standard aligns with international ICO protocols and evaluates green coffee based on two primary metrics: Defect Count (which determines the Grade: G1, G2, etc.) and Screen Size (which determines the physical size of the bean: S18, S16, S13).
1. Quality Grades (Defects)
Grades are determined by the maximum number of defects found in a 300g sample. Defects include black beans, broken beans, foreign matter (sticks, stones), and insect-damaged beans.
| Grade | Max Defects / 300g | Foreign Matter Max | Moisture Max |
|---|---|---|---|
| Grade 1 (G1) | 30 | 0.1% | 12.5% |
| Grade 2 (G2) | 60 | 0.5% | 12.5% |
| Grade 3 (G3) | 90 | 1.0% | 13.0% |
2. Screen Sizes
Screen size is measured in 1/64ths of an inch. A "Screen 18" bean means it will not fall through a sieve with holes measuring 18/64 of an inch (7.1mm).
| Screen Name | Hole Size (mm) | Requirement |
|---|---|---|
| Screen 18 (S18) | 7.10 mm | ≥ 90% retention on screen |
| Screen 16 (S16) | 6.30 mm | ≥ 90% retention on screen |
| Screen 13 (S13) | 5.00 mm | ≥ 90% retention on screen |
Common Export Designations
When buying Vietnamese coffee, the grade, screen size, and processing method are combined to create the product name. For example:
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Robusta G1 S18 Clean: Grade 1 (max 30 defects), large beans (Screen 18), standard processing (Clean/Natural).
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Robusta G1 S16 Wet Polished: Grade 1 (max 30 defects), medium beans (Screen 16), premium Wet Polished process for a cleaner cup.