How Does the Coffee Grading System Work for Green Coffee Beans?

Labels such as Yirgacheffe G2 and Kenya AA show the grade of a batch of green coffee beans. Each producing country runs its own coffee grading system, judging factors like bean size, defect ratio, growing altitude, bean hardness, and cupping score, so the same letters and numbers mean different things from origin to origin.

Ethiopia's pre-ECX grades were set by the CLU based mainly on defective beans in a 300-gram sample, with washed beans at G1 to G2 and natural beans mostly G3 to G5 until drying improved. After the ECX formed in 2008, physical traits and cup quality were combined. Kenya, Tanzania, Central and South America, Colombia, Brazil, and Jamaica are also covered.

Friends who frequently buy coffee beans have surely seen labels like Yirgacheffe G2 and Kenya AA. These letters and numbers actually represent the grade of green coffee beans. Since each coffee-producing country has a different grading system, the evaluation criteria also vary, with factors such as bean size, defect ratio, growing altitude, bean hardness, and cupping score all potentially serving as the basis for grading. In this article, Front Street Coffee will walk you through the green bean grading rules of representative producing countries including Ethiopia, Kenya, Tanzania, Central and South American countries, Colombia, Brazil, and Jamaica, helping you understand the grade labels on packaging the next time you shop.

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When buying coffee beans, everyone has surely come across names like Yirgacheffe G2 and Kenya AA. These characters—G2, AA—actually reflect the grade of that batch of green coffee beans. Different producing countries have different ways of grading green beans, usually measuring from perspectives such as bean size, defect count, growing altitude, bean hardness, and cupping score. Front Street Coffee will now introduce the green bean grading standards of several representative producing countries.

Ethiopia

Before the establishment of the Ethiopia Commodity Exchange (ECX), the country's coffee export grades were set by the CLU (Cupping and Liquoring Unit) under the Ministry of Agriculture, with the evaluation based primarily on the number of defective beans in a 300-gram sample. The specific standards are shown in the table below.

Typically, washed beans are classified as G1 to G2, while limited by early sun-drying techniques, naturally processed green beans had more defects and mostly fell between G3 and G5. However, with continuous advances in sun-drying processing, naturally processed beans can now also reach the G1-G2 level.

After the ECX (Ethiopia Commodity Exchange) was established in 2008, the grading was changed to combine the physical characteristics of green coffee beans with cupping flavor characteristics for scoring and grading.

Based on processing method, ECX divides coffee into two types—unwashed and washed—and further into three categories:

a. Specialty: Few defective beans, outstanding cup flavor quality;

b. Commercial: Does not reach specialty level but is superior to the domestic consumption grade;

c. Local/Domestic: Coffee with more defective beans (such as immature beans), or with flavor deviations due to being out of season or improperly stored.

Among these, Specialty and Commercial are exported to the international market. ECX divides green beans into nine grades based on the combined score of physical attributes and cup flavor, with physical characteristics accounting for 40 points and cupping quality accounting for 60 points.

Physical characteristics (40%):

Washed: defect count (20%), appearance/size (10%), color (5%), odor (5%)

Unwashed: defect count (30%), odor (10%)

Afterwards, G1 to G3 are cupped again according to SCAA standards for a more detailed assessment of flavor performance. G1 and G2 scoring no less than 85 points are rated as Q1; G1, G2, and G3 scoring between 80 and 85 points are rated as Q2; G1, G2, and G3 scoring below 80 points are all classified as G3.

Q1 and Q2 are exported as specialty grade, while G4 to G9 maintain their original grading and are exported as commercial grade together with G3.

Kenya

Grading based on green coffee bean size

E (Elephant bean): E stands for Elephant. It is not the Maragogype variety of elephant bean, but rather a bean that develops abnormally, causing two seeds to intertwine and appear as one bean—it falls under the category of defects. A normal fruit contains two seeds facing each other, so one side is flat, called a flat bean or female bean. E-grade beans are two seeds that have fused together during growth, resulting in an oversized volume. E-grade beans are typically above 18 mesh (one mesh equals 1/64 inch), and their production is extremely rare.

AA: This grade is approximately 17 to 18 mesh (about 6.7 to 7.1 mm), and is the most commonly mentioned Kenyan coffee grade, often called AA TOP in the specialty coffee world, and is also a product promoted by many coffee shops. However, AA does not equate to the best flavor; bean size and flavor quality cannot be conflated.

AB: Most coffee beans fall into this grade. It is called AB because A is 6.80 mm and B is 6.20 mm, and beans of these two sizes (A-grade and B-grade) are mixed and sold together, hence the name AB, with sizes around 15 to 16 mesh (about 6.0 to 6.4 mm).

C: Bean size is approximately 14 to 15 mesh (about 5.6 to 6.0 mm), smaller than B-grade.

PB: Full name Peaberry, also called small round bean or male bean. Compared to regular flat beans, this bean is relatively rare, accounting for about one-tenth of all coffee beans. It occurs because only one seed develops within the fruit, resulting in a small, round bean. Since some people prefer the flavor of PB, it is sorted out and sold separately.

TT: These beans are light beans sorted from AA and AB by air separation machines. They tend to be lighter in weight, fail to meet hardness standards, and have cracks and defects.

T: Lighter beans sorted from C-grade beans, mixed with broken beans and even fragmented pieces.

MH/ML: These coffee beans are not for export. They are usually overripe beans that have fallen to the ground, of poor quality, accounting for about 7% of all coffee beans, and are supplied only to the Kenyan domestic market.

Tanzania Tanzania coffee grading system is very similar to Kenya's, both grading by green bean size

Grading by green bean hardness . At the same latitude and in the same plot, the higher the altitude, the greater the temperature difference between day and night, the longer the coffee growing cycle, the harder the bean, and the more nutrients absorbed, resulting in more prominent flavor compounds. Therefore, many producing countries in Central and South America from Mexico southward adopt this standard, such as Guatemala, Costa Rica, Panama and other Central American countries. When exporting green beans, these producing countries often have only the SHB grade.

Additionally, some countries use altitude as the grading basis. The higher the altitude, the greater the temperature difference between day and night, the longer the coffee growing period, the harder the bean, the more nutrients accumulated, and the more pronounced the flavor compounds. For example, Honduras, El Salvador, Nicaragua .

Colombia

Grading by coffee mesh size

Brazil

Brazil generally uses the NY grading method

Naming method: Country + Region (Port) + Grade Name + Cup Quality

For example: Brazil Santos NY.2 FC means Brazil Santos region grade 2, the beans with the best cupping performance.

Brazil considers that only completely defect-free beans qualify as NY.1, and in reality, there are no completely defect-free beans. Therefore, among Brazilian green beans, the best grade is NY.2.

Divided by cupping level into :

Fine Cup (FC), Fine, Good Cup (GC), Fair Cup, Poor Cup, Bad Cup

Jamaica

Jamaican coffee grading is generally distinguished by mesh size

Blue Mountain No. 1, No. 2, No. 3, and Blue Mountain Peaberry are the only coffees in the world exported in wooden barrels, with three specifications: 70 kg, 30 kg, and 15 kg. Other grades of Jamaican coffee are exported in 60 kg burlap sacks.

Today Front Street Coffee has shared these green bean grading methods of various producing countries and regions, hoping to be helpful to readers.

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The above content is compiled by CoffeeHunters, a coffee news website.