Coffee Bean Grading Systems (Part 2)

Common African Coffee Bean Grading Systems

African countries generally do not share a uniform grading system. In Ethiopia, for example, many indigenous wild coffee varieties produce smaller beans, making size-based grading less relevant. On the other hand, countries such as Kenya, Tanzania, and Uganda place a greater emphasis on bean size, using similar grading methods.

Ethiopia’s Coffee Bean Grading Method

Ethiopia grades beans according to the number of defects per 300 grams of green coffee. Defect counts range from very low to very high. Extremely rare, flawless beans are labeled “Z,” while beans with too many defects are labeled “UG” and are not permitted for sale. Below are the more common grades:

• Grade 1 (G1): Fewer than 3 defects; the highest level for both natural and washed coffees (recently, some natural coffees also achieve G1 status).
• Grade 2 (G2): 4–12 defects; the standard grade for washed coffees.
• Grade 3 (G3): 13–25 defects; the highest grade for natural coffees (historically, natural coffees often started at this grade).
• Grade 4 (G4): 26–45 defects; the standard grade for natural coffees.
• Grade 5 (G5): 46–90 defects; the basic export grade for natural coffees (usually commercial-grade beans).

Historically, Ethiopia considered washed processing to be higher-quality and more consistent, so G1 and G2 were for washed coffees, while G3 to G5 were for natural coffees. However, in recent years, many top-tier natural coffees have also been awarded G1 and G2 classifications.

Kenya’s Coffee Bean Grading Method

If you frequent specialty coffee shops, you may have heard of “Kenya AA.” In Kenya, coffee is graded according to bean size, shape, and hardness, resulting in seven main categories:

1. E: Sometimes referred to as “Elephant Beans.” These result from an unusual development where two seeds in a single cherry merge into one large bean. It’s a natural mutation and thus quite rare.
2. AA: Screen size of approximately 7.20 mm (between screens 17 and 18). Some traders further subdivide this into AA+ or AA++ (screens 18–20) for the largest beans within the AA grade.
3. AB: A combination of size A (6.80 mm) and size B (6.20 mm) beans, reflecting the typical range found in a single harvest.
4. PB (Peaberry): Formed when only one of the two seeds in a coffee cherry develops, creating a round bean. This occurs in lower quantities and is considered a distinct grade.
5. C: Beans measuring about 4.8–5.6 mm, smaller than AB.
6. TT: Light, less dense beans separated by an airflow mechanism from AA or AB grades. Often includes damaged or less dense beans.
7. T: Screen size below 12 (under 4.8 mm), consisting mostly of broken pieces or defective beans.
8. MH/ML: Extremely low-quality beans (overripe or fallen cherries, etc.) that are unsuitable for the market.

Grades TT, T, and MH/ML typically consist of defective or broken beans and are not sold commercially. Additionally, exporters may use their own labels—such as TOP, Plus, FAQ (Fair Average Quality), or Specialty—even though these are not official government standards. They can, however, be useful indicators of quality.

Other Coffee-Producing Countries

For instance, Papua New Guinea in Oceania employs a grading system similar to Kenya’s. Meanwhile, Indonesia uses a defect-based grading method akin to Ethiopia’s, though it is generally more lenient. Below is a comparison.

Indonesia’s Coffee Bean Grading Method

Although Indonesia uses the same grade labels as Ethiopia, it allows for a higher defect count within each grade. As a result, the permissible number of defective beans is greater, even under the same grade name:

• Grade 1 (G1): Fewer than 11 total defects
• Grade 2 (G2): 12–25 total defects
• Grade 3 (G3): 26–44 total defects
• Grade 4a (G4a): 45–60 total defects
• Grade 4b (G4b): 61–80 total defects
• Grade 5 (G5): 81–150 total defects
• Grade 6 (G6): 151–225 total defects

Additionally, Indonesia features a hand-sorting frequency classification:

• Double-Picked (DP): Manually sorted twice
• Triple-Picked (TP): Manually sorted three times

Common International Standards

Many countries also recognize international grading references such as:

• US Preparation (USP) or American Preparation (AP)
• European Preparation (EP)
• Gourmet Preparation (GP)
• Japanese Preparation (JP)

These standards typically specify acceptable defect levels or screen sizes for green coffee beans. EP standards are generally stricter than USP standards and are more commonly used worldwide.

By understanding these diverse grading systems—from Africa to Southeast Asia and beyond—you’ll be better equipped to evaluate coffee beans and make more informed purchasing decisions.