Why Grading Exists
Green coffee grading systems classify unroasted coffee by physical and, increasingly, sensory attributes. Grading serves multiple purposes in the supply chain: it establishes a common vocabulary between buyers and sellers who may never meet in person, it sets quality tiers that correspond to price levels, and it provides contractual specifications against which delivered coffee can be measured and disputes resolved.
No single global grading standard exists. Each producing country developed its own system, often reflecting colonial-era trade requirements, local agronomic conditions, and the priorities of that country’s dominant buyer markets. The result is a patchwork of overlapping and sometimes contradictory classification schemes that specialty buyers must learn to navigate.
SCA Green Coffee Grading Protocol
The Specialty Coffee Association provides the closest thing to an international standard for physical green grading. The SCA protocol evaluates a 350-gram sample for defects, classifying each defect as either a Category 1 (full) defect or a Category 2 (partial) defect.
Category 1 defects include full black beans, full sour beans, fungus-damaged beans, foreign matter, dried cherry, and severe insect damage. A single Category 1 defect disqualifies a sample from specialty classification. Category 2 defects include partial black, partial sour, broken or chipped beans, immature or unripe beans (quakers), shells, and slight insect damage. Specialty-grade coffee must have no more than five Category 2 defects in a 350-gram sample.
Beyond defect counting, the SCA protocol also evaluates moisture content (target: 10 to 12 percent for arabica), water activity (target: below 0.70 aw for storage stability), screen size distribution, and odor (no off-odors such as ferment, chemical, or smoke). A sample that passes physical grading then proceeds to cupping evaluation, where it must score 80 points or above on the SCA cupping form to earn specialty designation.
Screen Size Classification
Screen size refers to the physical dimensions of green beans, measured using perforated metal screens with circular or oblong holes. Screens are numbered by the diameter of the hole in sixty-fourths of an inch. A Screen 18 bean passes through a screen with 18/64-inch holes (approximately 7.1 mm) but is retained on a Screen 17 (6.7 mm).
Screen size does not directly correlate with cup quality, but it serves as a proxy for bean density and maturity, which do influence flavor. Larger, denser beans tend to come from higher altitudes, longer maturation periods, and better-nourished plants. However, some excellent coffees produce small beans (notably peaberries and certain Ethiopian varieties), and some large beans produce unremarkable cups.
Country-Specific Grading Systems
Kenya: AA, AB, PB, and the Auction System
Kenya uses a screen-size-based grading system that is among the most recognized in specialty coffee. AA denotes beans retained on Screen 17/18 (the largest). AB combines Screen 15/16 beans. PB (Peaberry) designates single-lobed beans that develop when only one seed forms inside the cherry instead of the usual two. Other grades include C (Screen 14/15), TT (light density beans separated by air sorting from AA and AB), T (smallest and lightest fragments), and E (Elephant, unusually large or fused beans).
Kenyan grading does not directly assess cup quality. That happens at the weekly auction in Nairobi, where licensed auction buyers cup and bid on lots. The combination of screen grade and auction price effectively creates a quality hierarchy: Kenya AA from a top-performing cooperative in Nyeri or Kirinyaga might sell for multiples of what a Kenya AB from a less regarded region fetches.
Ethiopia: Grade 1 through Grade 5
Ethiopia grades coffee on a numerical scale from Grade 1 (highest) to Grade 5 (lowest), based on defect counts and cup quality. Grade 1 allows no more than 3 defects per 300-gram sample and must have no cup defects. Grade 2 allows 4 to 12 defects. Grades 3 through 5 represent progressively higher defect tolerances.
For washed Ethiopian coffees, Grades 1 and 2 are standard in specialty trade. For naturals, Grade 3 was historically common because the natural process inherently produces more physical defects (uneven drying, over-fermentation, insect damage during drying). In recent years, improved natural processing has made Grade 1 naturals more common from top-tier washing stations.
Ethiopian coffee is further classified by region (Sidama, Yirgacheffe, Guji, Limu, Jimma, Harrar, etc.) and by washing station or cooperative. The combination of grade, region, and specific station tells experienced buyers far more about quality expectations than the numerical grade alone.
Colombia: Supremo, Excelso, and Regional Designations
Colombia classifies export coffee primarily by screen size. Supremo is retained on Screen 17 and above. Excelso is Screen 14 to 16. UGQ (Usual Good Quality) is a commercial blend of sizes. These classifications are regulated by the Federacion Nacional de Cafeteros (FNC) and apply to all Colombian export coffee.
For specialty purposes, Colombian coffee is increasingly differentiated by department (Huila, Nariño, Cauca, Tolima, Antioquia, etc.), municipality, farm name, variety, process, and cupping score rather than by the Supremo/Excelso classification. A Supremo grade ensures a minimum bean size but says nothing about cup quality, origin specificity, or traceability.
Brazil: Santos and Type Classification
Brazil, the world’s largest producer, uses a complex grading system based on defect counting, screen size, cup quality, and bean color. The Type system ranges from Type 2 (fewest defects, near-perfect) to Type 8 (high defect count). Type 2/3 is standard for specialty, while Types 4 through 6 are commercial grades.
Screen sizes are designated by number (17/18 for the largest). Cup quality is classified from Strictly Soft (best) through Soft, Softish, Hard, Riado (slight iodine taste), Rio (strong medicinal/phenolic), and Rio Zona (extremely defective). Brazilian coffee is also classified by color: Greenish, Green, Yellowish Green, or Yellow.
The term Santos historically referred to coffee exported through the port of Santos and implied a certain quality standard. It remains in use but is less meaningful for specialty buyers who specify farm, region, variety, and process.
Guatemala: SHB, HB, and Altitude Grades
Guatemala grades coffee by the altitude at which it was grown. SHB (Strictly Hard Bean) denotes coffee grown above 1,350 meters. HB (Hard Bean) covers 1,220 to 1,350 meters. Semi Hard Bean is 1,050 to 1,220 meters. EPW (Extra Prime Washed) and PW (Prime Washed) cover lower altitudes.
The logic is sound: higher altitude generally means cooler temperatures, slower cherry maturation, denser beans, more complex sugar development, and better cup quality. SHB is the minimum grade for specialty Guatemalan coffee. Within SHB, further differentiation comes from region (Antigua, Huehuetenango, Acatenango, Atitlan, Coban, etc.), farm, variety, and cupping score.
Costa Rica, Honduras, and Other Central American Origins
Most Central American countries use altitude-based systems similar to Guatemala’s. Costa Rica uses SHB (above 1,200 meters), GHB (Good Hard Bean, 1,000 to 1,200 meters), and HB (800 to 1,000 meters). Honduras uses SHG (Strictly High Grown), HG (High Grown), and CS (Central Standard). El Salvador and Nicaragua follow comparable conventions.
The Specialty Threshold and Its Limitations
The 80-point cupping score threshold for specialty classification has become the industry’s most important quality gate. It combines physical grading (defect counting) with sensory evaluation (cupping) into a single pass-fail standard. Coffee scoring 80 or above enters the specialty market with its higher prices and differentiated branding. Coffee scoring below 80 is classified as commercial and trades at or near C-market prices.
This binary threshold obscures enormous quality variation on both sides of the line. An 80-point coffee and a 90-point coffee are both specialty, but they represent vastly different quality levels and serve different market segments. Similarly, a 79-point coffee may be functionally indistinguishable from an 80-point coffee, yet one enters the specialty channel and the other does not.
The subjectivity of cupping scores, the variation between graders, and the influence of sample preparation and roast profile on scoring outcomes mean that the 80-point threshold, while useful as a market organizing tool, is an imperfect measure of absolute quality.