Introduction:When selecting coffee beans, have you ever been puzzled by markings like G1, AA, or PB on the packaging? These letters actually represent different green bean grading systems used in various origins, directly influencing flavor and price. This article delves into the grading logic of major producing regions such as Ethiopia, Kenya, and Colombia—from defect ratios, bean size to cupping scores—to help you accurately understand the quality implications behind the labels and choose the coffee beans that best suit you.
When you stand in front of a coffee bean display, have you ever been baffled by markings like G1, AA, or PB on the packaging? These seemingly simple letters are actually important indicators used by different origins to distinguish coffee bean quality. Understanding these grading systems not only helps you make smarter choices but also allows you to delve deeper into the stories behind the coffee.
Take Ethiopia as an example. Before the establishment of the Ethiopian Commodity Exchange (ECX), the country’s coffee grading was primarily based on the ratio of defective beans. At that time, the CUPping and Liquoring Unit (CLU) under the Ministry of Agriculture would inspect the number of defective beans in a 300-gram sample and classify the coffee beans into five grades from G1 to G5 accordingly. Generally, washed coffee beans have fewer defects and are mostly classified as G1 or G2; whereas traditional natural processed beans, due to technical limitations, tend to have a higher defect ratio and are often categorized as G3 to G5. However, with advancements in natural processing techniques, many natural beans nowadays can also meet the high standards of G1 or G2.
After the establishment of the ECX in 2008, the grading method underwent significant reforms. The new system no longer relies solely on defect counts but takes a comprehensive approach by considering both the physical characteristics of the green beans and their cupping flavor performance, dividing coffee into nine grades. In the scoring mechanism, physical characteristics account for 40%, including processing method, appearance size, color, and aroma; cupping quality makes up 60%. Among them, the scoring weights for physical characteristics slightly differ between washed and non-washed beans. For instance, washed beans are evaluated based on defect count (20%), appearance size (10%), color (5%), and aroma (5%), while non-washed beans place more emphasis on defect count (30%) and aroma (10%).
Based on the combined performance of cupping and physical characteristics, green beans are classified from Grade 1 to Grade 9. Grade 1 requires the defect count to be kept below 3 per 300 grams, while Grade 2 allows 4 to 12 defects, and so on, with Grade 5 tolerating up to 90 defects. Notably, the ECX conducts further SCAA-standard cuppings on G1 to G3 samples; those scoring above 85 points are rated as Q1 grade, considered top-tier specialty coffee; scores between 80 and 85 are classified as Q2 grade; and those below 80 are demoted back to G3 grade. Ultimately, Q1 and Q2 are exported as specialty beans, while G4 to G9 are collectively categorized as commercial grades.
Turning to another major African origin, Kenya, its grading system is mainly based on coffee bean size. Kenyan coffee beans are divided into eight grades, among which Grade AA is the most common and most notable grade, with a bean size of approximately 17 to 18 mesh (about 6.7 to 7.1 millimeters). It is quite popular in the specialty coffee market and is often labeled as AA TOP. However, it’s worth noting that bean size does not directly equate to flavor quality but merely represents the uniformity and size of the beans.
Grade E is a special category in the Kenyan grading system. These beans consist of two seeds that stick together in the fruit, forming larger-than-usual beans. Although they exceed 18 mesh in size, they are considered defective beans due to abnormal development and are also very rare. Grade AB is a blend of Grade A (approximately 6.8 millimeters) and Grade B (approximately 6.2 millimeters), with a size of about 15 to 16 mesh, and is one of the most widely circulated grades in the market.
Grade PB, or Peaberry, is another special classification. Normally, coffee cherries contain two flat beans, but about 10% of the cherries develop only one round seed—this is Grade PB. Due to their rarity and the fact that some enthusiasts believe they have unique flavors, they are often sorted and sold separately. Additionally, Grades TT, T, MH/ML represent light beans, broken beans, and overripe beans, respectively. Most are unsuitable for export and are only used for domestic consumption or lower-end markets.
Besides Ethiopia and Kenya, other origins also have their own grading logics. For example, countries like Colombia, Jamaica, and some South American nations grade coffee based on cupping scores, typically ranging from Grade 1 to Grade 9, where Grade 1 represents the highest quality with cupping scores reaching 91 to 100. Meanwhile, countries like Costa Rica, Panama, and Guatemala often use green bean hardness or altitude as grading criteria—the higher the altitude and the harder the beans, the more it usually indicates richer flavors.
Brazil adopts a multifaceted grading standard, taking into account bean size, defect rate, and cupping flavor. Brazil’s NY grading system classifies beans by size, using SC (Screen Size) to denote mesh numbers—for example, 17/18 mesh represents larger beans. Additionally, Brazil evaluates defect counts and provides flavor ratings such as FC (Fine Cup) or Good Cup (GC) through cupping. For instance, beans labeled as Brazil Cerrado NY-2 SC-17/18 FC mean they are from the Cerrado region, classified as Grade 2 under the NY system, with a bean size of 17 to 18 mesh, and cupped as Fine Cup (FC).
In summary, from Ethiopia’s defect ratio and cupping scores, to Kenya’s bean size classification, to other origins’ grading by altitude, hardness, and flavor ratings—each grading system reflects the industry characteristics and quality requirements of its region. Understanding these grading standards can give you more direction when purchasing coffee beans, helping you find the product that best matches your taste and budget.
The above content is compiled by CoffeeHunters, a coffee news website.
