Understanding Vietnamese Robusta Grading: S13, S16, S18

Vietnamese Robusta coffee is classified primarily by screen size — the diameter of the circular hole through which green beans are sorted. The three principal commercial grades are S13 (screen 13, beans passing through a 5.0mm sieve), S16 (screen 16, 6.3mm), and S18 (screen 18, 7.1mm). This classification system, standardized under TCVN 4193:2014, determines not only pricing but also the suitability of each grade for specific end uses. Understanding these distinctions is essential for any importer or manufacturer sourcing Vietnamese Robusta.

S18 grade represents the largest and most uniform beans, typically commanding a premium of $200-350 per metric ton above the ICE London Robusta futures benchmark. S18 beans are prized for their clean cup profile, lower bitterness relative to smaller screens, and consistent roast development. Japanese instant coffee manufacturers — the single largest buyer segment for Vietnamese Robusta — specify S18 for their premium product lines because the larger bean size yields a more balanced extraction during spray-drying. VCG's S18 output consistently achieves fewer than 5% defects by weight, with moisture content maintained at 12.0-12.5% per TCVN standards.

S16 is the workhorse grade of Vietnamese Robusta, accounting for approximately 55% of total export volume. It offers a strong price-to-quality ratio, trading at $80-150 per ton above London futures. S16 is widely used in espresso blends across Europe and the Middle East, where its body and crema-producing characteristics complement Arabica components. In the ready-to-drink (RTD) coffee segment in Japan and Korea, S16 is the standard input for products where cost efficiency matters but base quality must remain high. VCG supplies S16 with a maximum 8% defect rate and moisture between 12.5-13.0%.

S13 grade, the smallest commercially traded screen size, trades at or near the London futures price. While sometimes perceived as a lower-quality grade, S13 has important applications in industrial instant coffee production, 3-in-1 mixes, and extract manufacturing where yield per kilogram — rather than cup complexity — is the primary concern. Large-volume buyers in China, Russia, and Southeast Asia often prefer S13 for its cost effectiveness. VCG processes S13 to a maximum 10% defect rate, and we offer custom moisture specifications between 12.5-13.5% depending on buyer requirements.

Beyond screen size, VCG applies additional quality parameters that differentiate our Robusta from commodity-grade competitors. These include: black bean count (maximum 1% for S18, 2% for S16), foreign matter content (maximum 0.5%), and cup quality assessment by our in-house Q-graders. We also offer specialty preparation options including hand-picking for zero-defect lots, polishing for improved visual appearance, and custom moisture profiling for buyers with specific roasting equipment requirements. Every shipment is accompanied by a Certificate of Quality issued by CAFECONTROL, Vietnam's authorized coffee inspection body.