The grading system for green coffee beans directly affects roasting outcomes and coffee quality. This article systematically outlines two mainstream grading methods: classifying bean size by screen mesh number, and assigning grades based on growing altitude. It also compiles common grading standards and codes from origins such as Kenya, Ethiopia, Colombia, Brazil, Guatemala, El Salvador, Hawaii, Jamaica, and Indonesia. Whether for bulk trade or specialty coffee, understanding these grading rules helps more accurately assess green bean characteristics, and Front Street Coffee also incorporates this knowledge into its daily bean selection and roasting practices.

Green coffee bean grading methods fall mainly into two categories: one based on screen mesh number, and the other based on altitude.

Screen mesh grading uses "mesh" as the unit of size.

Peaberries are usually smaller than flat beans, with peaberries ranging from 8 to 13, and flat beans ranging from 12 to 29.

8, 9, 10…12, 13…18…29 correspond in turn to small, medium, regular… near-large… large, extra-large. The higher the number, the larger the bean size. For example, SC-19 represents No. 19 beans.

Grading by Altitude

Based on the altitude of the coffee-growing area, seven grades can be distinguished. Overall, beans grown at high altitudes are superior in quality to low-altitude beans, and because transportation costs rise, their prices are correspondingly higher.

No.　　Grade　　Abbreviation　　Altitude

1　　Strictly Hard Bean　S.H.B　4500~

2　　Hard Bean　H.B　4000~4500

3　　Semi-Hard Bean　S.H　3500~4000

4　　Extra Prime Washed　E.P.W　3000~3500

5　　Prime Washed　P.W　2500~3000

6　　Extra Good Washed　E.G.W　2000~2500

7　　Good Washed　G.W　~2000

The purpose of grading is to make green bean size more uniform, facilitating the roasting process, while also enhancing the commercial value of the green beans themselves.

Screen Mesh Diameter

The internationally accepted size range is 9 to 22. The number used indicates the screen mesh diameter, expressed as a fraction with that number as the numerator and 64 as the denominator, in inches. For example, 14 means the green beans can pass through a screen with a 14/64-inch mesh; 19+ means the green beans can pass through a screen with a 19/64-inch or larger mesh.

Grading Standards and Codes

Each coffee-exporting country's government establishes its own grading standards and grade codes.

Common Grading Standards

Considerations for bulk trade:

Proportion of defective beans

Bean size

Bean hardness

Single-origin coffee (specialty coffee) focuses on:

Name of the producing farm

Organic cultivation (organic)

Fair trade

African Country — Kenya

PB: peaberry

AA Plus-plus

AA plus

AA :Screen 17 and 18

AB : screen 15 and 16

C

E

African Country — Ethiopia

Based on 300 grams of green beans

1: 0-3 defects

2: 4-12

3: 13-25

4: 20-45

5: 46-100

6: 101-153

7: 154-340

8: over 340 = substandard

South America — Colombia

Maragogype: special trees Maragogype, elephant bean

Supremo: screen >17

Excelso: screen 15-16.5

UGQ: Usual Good Quality: Screen 12-14

South America — Brazil

Type　Defects (COB)　(New York)　(Le Havre)

2 4　6　8

2/3　8　9 12.5

3　12　13 17

3/4　19　21　23.5

4　26 30　30

4/5　36 45　58.5

5　46　60　87

5/6　64　123

6　86　158

Central America — Guatemala

Good Washed: altitude 700m (GW)

Extra Good Washed: 700/850m (EGW)

Prime Washed: 850/1000m (PW)

Extra Prime Washed: 1000/1200m (EPW)

Semi Hard Bean: 1200/1350m (SH)

Hard Bean: 1350/1500m (HB)

Fancy Hard Bean: 1500/1600m (FHB)

Strict Hard Bean: 1600/1700 m (SHB)

Central America — El Salvador

Washed

Central Standard: 500/900 m (CS)

High Grow: 900/1200 m (HG)

Strictly High Grown: >1200 m (SHG)

Natural

Coriente

Superior

Caracoil

Hawaii Kona

Kona Extra Fancy: screen 19 maximum 10 defects

Kona Fancy: Screen 18 max. 16 defs.

Kona Prime: no size requirement max. 25 defs.

Kona Caracoli No.1: Screen 10 max. 20 defs.

Jamaica

Blue Mountain

High Mountain Supreme

Prime Washed Jamaica aica

Grade Grade

Grade I: screen 18

Grade II: screen 17

Grade III: screen 16

Peaberry

Indonesia

Grade based on 300g

1: 11 defects

2: 12-25

3: 26-44

4a: 45-60

4b: 61-80

5: 81-150

6: 151-225

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