What Do Green Coffee Beans Grades Like G1 and AA Mean?

Green coffee bean grades are national systems, not one global scale. Ethiopia's G1 and G2, Kenya's AA and AB, Jamaica's Blue Mountain No. 1, and Costa Rica's SHB all reflect how a producing country judges quality, using criteria such as defect ratio, bean size, altitude, density, and processing method.

History, trade interests, climate, and topography shaped each system, so a grade from one country cannot be directly compared with a grade from another, and defect calculations differ as well. Grading evaluates green bean quality only; it does not settle whether a coffee tastes good in the cup.

Coffee enthusiasts often ask in the shop what exactly the difference is between Ethiopia's G1 and G2, what Kenya AA represents, and what Costa Rica's SHB grade means. These combinations of letters and numbers actually reflect how each producing country evaluates the quality of green coffee beans. Due to differences in history, trade, climate, and topography, different origins have developed their own grading systems, with evaluation criteria covering multiple dimensions such as defect ratio, bean size, growing altitude, green bean density, and processing method. This article will systematically sort out the origins of coffee grading and introduce one by one the green bean grade standards of representative producing countries such as Ethiopia, Kenya, Colombia, Jamaica, Costa Rica, Panama, Guatemala, El Salvador, Honduras, and Brazil.

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Many friends, when drinking coffee at Front Street shops, curiously ask the baristas: What exactly is the difference between Yirgacheffe G1 and G2? What do Kenya AA and AB represent? What does Costa Rica SHB grade mean? In fact, these codes are all ways different regions evaluate the quality of green coffee beans. So why do coffee beans need to be graded? Next, Front Street will walk everyone through the coffee grading system and introduce the green bean grade standards of several representative producing countries.

What is coffee bean grading?

In order to distinguish high-quality coffee beans from poorer-quality beans, producers must grade coffee. The basis for grading usually includes defect bean ratio, screen size, growing altitude, green bean density, and processing standards. However, because each country's historical background, trade interests, climate conditions, and topographical features are different, we cannot use a single unified standard to measure coffee from all regions, nor can we use the same method of calculating defects, or judge quality simply by altitude, and even less can we directly compare a certain grade from one country with a certain grade from another country. This approach is neither accurate nor objective. Front Street has always believed that whether a coffee tastes good or not cannot be determined entirely by green bean grade. Grading is only an evaluation of green bean quality, while coffee flavor is also affected by many factors such as growing conditions and soil environment. Therefore, when tasting a coffee, one should not conclude that it must taste better than a lower-grade coffee simply because its grade is high.

Let's now look at the green bean grading systems of several representative producing countries.

Ethiopia (graded by defect bean ratio)

Before the establishment of the Ethiopia Commodity Exchange (ECX), Ethiopia's coffee export grades were set by the CLU department (Cupping and Liquoring Unit) under the Ministry of Agriculture, mainly grading according to the number of defect beans contained in 300 grams of coffee beans, with specific standards shown in the table below. Generally speaking, washed coffee beans are G1 to G2 grades, while because early natural processing techniques were not mature enough, natural green beans had a relatively high number of defects, usually G3 to G5. With the continuous improvement of natural processing techniques, natural beans can now also reach G1 to G2 grades.

After the establishment of ECX (Ethiopia Commodity Exchange) in 2008, grading was changed to a comprehensive score combining the physical attribute characteristics of green coffee beans and cup flavor characteristics.

ECX divides all coffee into two types according to processing method, non-washed and washed, and further divides them into three major categories:

a. Specialty: Few defects, high cup flavor quality.

b. Commercial: Does not reach specialty grade, but is higher than the domestic consumption grade.

c. Local/Domestic: Coffee with a large number of defect beans (such as immature beans), or relatively poor flavor due to being out of season or poorly stored.

Among them, specialty and commercial grades are aimed at the export international market. Based on the total score of physical attribute characteristics and cup flavor characteristics, ECX divides green coffee beans into nine grades, with physical characteristic score accounting for 40% and cup quality score accounting for 60%.

Physical characteristics (40%):

Washed processing: number of defects (20%), appearance size (10%), color (5%), odor (5%)

Non-washed processing: number of defects (30%), odor (10%)

Then G1 to G3 are cupped again according to SCAA standards to evaluate their flavor attributes in more detail. G1 and G2 scoring no less than 85 are rated Q1; G1, G2, and G3 scoring between 80 and 85 are rated Q2; all G1, G2, and G3 scoring below 80 are rated G3.

Q1 and Q2 are classified as specialty grade for export. G4 to G9 remain unchanged in their original grading and are classified as commercial grade for export together with G3.

Representative Ethiopia G1 grade coffee beans — Front Street Coffee (FrontStreet Coffee) natural Red Cherry coffee beans

Region: Yirgacheffe Variety: local heirloom varieties Altitude: 1800-2000m

Processing method: natural

Kenya (graded by bean size)

Kenyan coffee grading is mainly based on coffee bean size and is usually divided into eight grades. There are also many other countries that grade by green bean size, such as Tanzania, Rwanda, Colombia, Jamaica, and others.

E (Elephant bean): Here "E" stands for Elephant, but it is not the Maragogype elephant bean variety in coffee; rather, it is a bean caused by abnormal development in which two seeds become intertwined and form what looks like "one bean," and it belongs to defect beans. Normally, one fruit contains two seeds facing each other, so one side is flat, called a flat bean or mother bean. E-grade beans are when two seeds fuse and stick together during growth, becoming especially large. E-grade beans are about 18 screen size (one screen is 1/64 inch) or above, and are rare in number.

AA: This grade is about 17 to 18 screen size (about 6.7 to 7.1 mm), and is the Kenyan coffee grade most people have heard of. In specialty coffee, this grade is usually called AA TOP, and it is also the bean many coffee shops promote. But AA does not mean the best; it is only an indicator of bean size and cannot be confused with flavor.

C: Bean size is roughly between 14 and 15 screen size (about 5.6 to 6.0 mm), slightly smaller than grade B.

PB: Full name Peaberry, also called small round bean, or male bean. Compared with ordinary flat beans, PB beans account for about 10% of all coffee beans, mainly because only one seed develops fully inside the fruit, resulting in a small, round bean. Some people especially love the flavor of PB, so PB is selected out and sold separately. Many people think PB beans are rare, but in fact PB beans can also be considered a type of defect bean.

TT: This type of coffee bean is screened out from AA and AB beans by an airflow sorter as light beans, usually lightweight, failing to meet hardness standards, and containing broken and defect beans.

T: Lighter beans screened from grade C beans, mixed with broken beans, and even fragments of shattered beans.

MH/ML: This type of coffee bean is not used for export. It is usually overripe fallen coffee beans with poor quality, accounting for about 7% of all coffee beans, and is only supplied to Kenya's domestic market.

AB: Most coffee beans belong to this grade. It is called AB mainly because the screen size of A is 6.80 mm and that of B is 6.20 mm, and these two sizes of coffee beans (grade A and grade B) are sold mixed together, so it is called AB, about 15 to 16 screen size (about 6.0 to 6.4 mm).

Representative Kenya AA grade — Front Street Kenya Little Tomato coffee beans

Region: Thika, Kenya Altitude: 1550–1750 meters Grade: AA TOP Variety: SL28, SL34 Processing method: Kenyan 72-hour washed

Colombia

Most regions in Colombia have already switched to faster-growing coffee trees, meaning the goal is placed on the high-end commercial coffee market. If it is the highest-grade commercial coffee bean, it is not necessarily worse than "specialty beans" from other regions. The No. 18 beans further selected from Supremo, namely Supremo 18, have good flavor and also often appear in specialty coffee shops.

Jamaica

According to the altitude of the coffee-growing mountains and the size of the raw beans, Blue Mountain coffee is divided into three grades: Jamaica Blue Mountain Coffee, Jamaica High Mountain Coffee, and Jamaica Prime Washed Coffee. Of course, ordinary Jamaican coffee is called "Jamaica Coffee," mainly produced in mid- and low-altitude mountain areas, and belongs to the Jamaica Prime Washed coffee series. Blue Mountain coffee bean exports are further divided into 7 grades:

Blue Mountain No. 1: 96% of coffee beans must be screen size 17/18, with no more than 2% defect beans. Blue Mountain No. 2: 96% of coffee beans must be screen size 16, with no more than 2% defect beans. Blue Mountain No. 3: 96% of coffee beans must be screen size 15, with no more than 2% defect beans. Blue Mountain Peaberry: 96% of coffee beans must be screen size 10 single round peaberry beans, with no more than 2% defect beans. Blue Mountain Triage: A blend of Blue Mountain No. 1, No. 2, and No. 3 beans, with a small number of slight defect beans, but without affecting the cup quality of the coffee. Blue Mountain Fine Beans: Coffee beans below screen size 15, with no more than 2% defect beans. This portion of beans is sold only in sample mode, and the price is determined by demand conditions. Blue Mountain Triage Peaberry: A blend of Blue Mountain peaberry beans, with a small number of slight defects, but very good cup quality, with no more than 4% defect beans.

Representative Blue Mountain No. 1 grade: Front Street Coffee (FrontStreet Coffee) Jamaica Blue Mountain No. 1 coffee

Farm: Clifton Farm

Owner: The Sharp family Certification: Rainforest Alliance certification Location: Newcastle area Total area: 250 acres Coffee planting area: 180 acres Average altitude: 4300 feet (1310.64 meters) Processing method: washed Variety: 100% Arabica Typica

Costa Rica, Panama, Guatemala (graded 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 growth period, the harder the beans, the more nutrients absorbed in the beans, and the more pronounced the flavor substances.

Representative Costa Rica SHB — Front Street Costa Rica Musicians Series Beethoven coffee beans

Coffee region: Tarrazu region Grading standard: SHB Coffee variety: Yellow Catuai Processing method: washed processing Growing altitude: 1980M

El Salvador, Honduras (graded by altitude)

Brazil (graded by bean size, defect rate, and cup score)

Brazil considers that only beans with completely no defects can become NY.1, and beans with completely no defects do not exist. Therefore, among Brazilian green beans, the best is NY.2.

By number of defect beans

Divided by cup grade into:

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

For example: Brazil Cerrado NY-2 SC-17/18 FC

It means the Brazil Cerrado region's NY grading method is 2, the coffee bean size is 17-18 screen size, and the flavor quality is Fine Cup (excellent flavor).

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