A Comprehensive Guide to Global Coffee Bean Grading Systems and Coffee Origin Green Bean Classification Standards

Coffee Bean Grading Standards: A Complete Guide

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When you buy coffee beans, you've probably heard of Yirgacheffe G2, Kenya AA, and similar terms. These designations like G2 and AA represent the grade of the green coffee beans. Each coffee-producing country has different standards for grading green beans. Today, FrontStreet Coffee will share the green bean grading standards from several representative coffee-producing countries.

Coffee Grading and Classification

Coffee bean grades are typically determined by defect rates, bean size, altitude, green bean density, processing standards, and other factors. Each country's growing region cannot be graded by unified standards or simply by altitude due to various factors including historical reasons, trade interests, climate, and terrain. Nor can grades from one country be directly compared with those from another country.

1. Ethiopia (Graded by Defect Bean Percentage)

Before the establishment of the Ethiopia Commodity Exchange (ECX), Ethiopia's coffee export grades were set by the CLU (Cupping and Liquoring Unit) under the Ministry of Agriculture, primarily based on the number of defective beans in 300g samples. The grading standards are as shown in the table below.

Grade: Number of defective beans (per 300g)

Generally, washed coffees are graded G1-G2. Due to technical issues with natural processing at that time, natural processed beans had more defects and were typically graded G3-G5. With improvements in natural processing technology, current natural processed beans can also achieve G1-G2 grades. After the ECX was established in 2008, coffee beans are graded using a combination of physical attribute characteristics and cupping flavor characteristics.

The ECX classifies all coffee into three types based on processing method (non-washed and washed):

a. Specialty: Few defects, high cupping flavor quality

b. Commercial: Does not reach specialty grade but is higher than the domestic (Local/Domestic) consumption grade

c. Local/Domestic: Coffee with many defective beans (unripe), out-of-season, or poorly stored resulting in relatively poor flavor

Among these, Specialty and Commercial are for the international export market. The ECX divides coffee beans into nine grades based on the total score of physical characteristics and cupping quality, where physical characteristics account for 40% and cupping quality accounts for 60%.

Physical Characteristics (40%):

Washed processing: Defect count (20%), appearance size (10%), color (5%), odor (5%)

Non-washed processing: Defect count (30%), odor (10%)

2. Cupping Quality (60%)

Grade Score Washed Non-washed

Then, G1-G3 beans are re-cupped according to SCAA standards for more detailed flavor attribute assessment. G1 and G2 beans scoring no less than 85 points are classified as Q1 grade; G1, G2, and G3 beans scoring between 80 and 85 points are classified as Q2 grade; and all G1, G2, and G3 beans scoring below 80 points are classified as G3 grade. Q1 and Q2 are classified as specialty coffee grades for export. G4-G9 maintain their original grading and are exported as commercial grades along with G3.

3. Kenya (Graded by Bean Size)

Kenya coffee bean grades are primarily based on bean size, typically divided into eight grades.

E (Elephant Beans): Here "E" stands for "Elephant," but this doesn't refer to the Maragogype variety. It's a defect caused by abnormal development where two seeds intertwine, forming what appears to be a single bean. Normally, a coffee fruit contains two seeds facing each other, creating one flat side - these are called flat beans or female beans. Grade E beans occur when two seeds fuse together during growth, creating oversized beans. Grade E beans are about 18 screen size (1 screen = 1/64 inch) or larger and are rare.

AA: This grade is about 17-18 screen size (approximately 6.7-7.1mm), the most commonly heard Kenya coffee grade. In specialty coffee, this grade is often called AA TOP and is promoted by many coffee shops, but AA doesn't necessarily mean the best - it's just about bean size, not flavor.

FrontStreet Coffee's Kenya Small Tomato grade is AA

AB: Most coffee beans fall into this grade. It's called AB mainly because grade A beans are 6.80mm and grade B beans are 6.20mm. These two sizes (A and B grades) are mixed together for sale, hence called AB. The size is about 15-16 screen (approximately 6.0-6.4mm).

C: Bean size approximately 14-15 screen (approximately 5.6-6.0mm), smaller than grade B.

PB: Full name is Peaberry, also called small round beans or male beans. Compared to regular flat beans, these are also rare, accounting for about 10% of all coffee beans. They occur when only one seed develops in the fruit, resulting in small, round beans. Some people particularly love PB flavor, so PB beans are sorted and sold separately.

TT: These are lightweight beans screened from AA and AB beans using air sorters. They are typically light in weight, don't meet hardness standards, and include broken and defective beans.

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

MH/ML: These coffee beans are not exported. They are typically overripe beans that have fallen to the ground, with poor quality, accounting for about 7% of all coffee beans, only for Kenya's domestic market.

Many other countries also grade by green bean size, such as Tanzania, Rwanda, Colombia, Jamaica, etc.

4. Colombia

Grade Size Standard

Jamaica

FrontStreet Coffee's Jamaica Blue Mountain belongs to NO.1 grade, commonly known as Blue Mountain No.1

5. Costa Rica, Panama, Guatemala (Graded by Bean Hardness)

At the same latitude and location, higher altitude means greater temperature differences between day and night, longer coffee growing periods, harder beans, more nutrients absorbed by the beans, and more pronounced flavor compounds.

Grade Altitude

FrontStreet Coffee's Panama Hacienda La Esmeralda Green Label Geisha belongs to SHB grade, Strictly Hard Bean.

6. El Salvador, Honduras (Graded by Altitude)

Grade Altitude (El Salvador) Altitude (Honduras)

FrontStreet Coffee's Honduras Sherry grade is SHG

7. Brazil (Graded by Bean Size, Defect Rate, and Cupping Score)

Brazil believes that only completely defect-free beans can become NY.1, but completely defect-free beans don't exist. Therefore, the best green beans in Brazil are NY.2.

Grading by coffee bean size (NY grading method)

Divided by cupping level:

Fine Cup (FC), Fine, Good Cup (GC), Fair Cup, Poor Cup, Bad Cup. For example: Brazil Cerrado NY-2 SC-17/18 FC means Brazil Cerrado region, NY grading method 2, coffee bean size 17-18 screen, flavor quality Fine Cup (excellent flavor).

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