Coffee bean grading systems

Coffee bean grading systems are methods used to evaluate and classify coffee beans based on their quality, size, origin, and defects. These systems vary by country and are often tied to national standards or export regulations. Here's a detailed overview of the main grading approaches used globally:

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☕ 1. By Bean Size (Screen Size Grading)

• Used in: Many countries including Kenya, Colombia, and Central American nations.

• Basis: Bean sizes are graded by passing green coffee beans through a series of standardized mesh screens, where holes are measured in 1/64ths of an inch. A size 18 screen represents 18/64ths of an inch. The beans are separated by size to ensure consistent roasting, as larger beans are often denser and take longer to roast, while smaller beans might burn

• Screen System (8–20): Beans are sorted, and the percentage remaining on each screen is recorded.

• Key Grading Methods & Sizes:  Eg:

  Grade /screen 18 or "AA": Considered large/premium, these are 18/64 inches or larger.
  Grade / screen 15 or "A"/"AB": Slightly smaller beans.

• • Screen 16 = 16/64 inch (medium)

  • Screen 14 = 14/64 inch (small)

• Typical Labels:

  • AA: Very large (Screen 18+)

  • AB: Medium-large (Screen 16–17)

  • C: Smaller (Screen 14–15)

  • Peaberry (PB): A natural mutation where only one round bean grows in a cherry instead of two.
    
    
  • Regional Differences: In the Americas, sizes can be grouped as high as Superior (size 17+) and as low as Terceras.

👉 Larger beans don’t necessarily mean better flavor, but they often roast more evenly.

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🌍 2. By Altitude or Growing Region

• Used in: Latin America (especially Central America).

• Basis: Higher altitudes tend to produce denser, harder beans with more complex flavors.

• Example (for Arabica beans):

  • Strictly Hard Bean (SHB) / Strictly High Grown (SHG): Grown above 1,200–1,400 m (4,000–4,600 ft)

  • Hard Bean (HB): 900–1,200 m

  • Medium / Low Grown: Below 900 m

• Countries using this: Guatemala, Honduras, Costa Rica, Panama, etc.

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🧾 3. By Defect Count (Quality / Cleanliness Grading)

• Used in: Ethiopia, Brazil, Colombia, and many others.

• Basis: Number and type of defects (broken beans, black beans, insect damage, etc.) in a 300–350g sample.

• Example:

  • Specialty Grade: 0–3 defects per 350g; excellent uniformity and cup quality.

  • Premium Grade: 4–8 defects.

  • Exchange Grade: 9–23 defects.

  • Below Standard: More than 23 defects.

• System reference: Specialty Coffee Association (SCA) cupping standards.

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🌱 4. By Cup Quality (SCA Cupping Score)

• Used globally in specialty coffee markets.

• Basis: Sensory evaluation by certified Q-graders.

• Scoring system (0–100 points):

  • 90–100: Outstanding (Rare)

  • 85–89.99: Excellent (Specialty)

  • 80–84.99: Very Good (Specialty)

  • <80: Below specialty grade

• Assessed attributes: Aroma, flavor, acidity, body, balance, sweetness, uniformity, aftertaste, and defects.

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🇧🇷 5. By Country-Specific Systems

Each coffee-producing country often has its own grading terminology and criteria. Examples:

Brazil:

• Uses NY (New York) grading and screen size.

• Grades like NY 2/3, NY 4/5 — lower numbers mean fewer defects.

Colombia:

• Grades by size and density: Supremo (screen 17/18), Excelso (screen 14–16).

Ethiopia:

• Grades 1 to 9 based on defects and cup quality:

  • Grades 1–2: Washed, specialty-grade

  • Grades 3–5: Natural or lower quality

  • Grades 6–9: Commercial/lower grades

Kenya:

• Grades mainly by screen size:

  • AA: Screen 18

  • AB: Screen 16–17

  • PB (Peaberry): Single round bean per cherry

  • C, TT, T: Smaller or broken beans

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🧡 Summary Table

Method	Focus	Example Grades	Typical Use
Size	Physical bean diameter	AA, AB, C	Kenya, Colombia
Altitude	Elevation/density	SHB, HB	Central America
Defect Count	Cleanliness/quality	NY 2/3, Grade 1	Ethiopia, Brazil
Cup Score	Sensory attributes	80+, 85+, etc.	Specialty coffee
National Standards	Country-specific	Supremo, Excelso, etc.	Colombia, Kenya