How Coffee Beans Are Graded by Size and Altitude

When you buy specialty coffee, have you ever wondered why some beans are labeled SHB or AA, while others are simply graded by size or altitude? The truth is, coffee beans are sorted and classified using multiple systems—some based on physical size, others on growing elevation—all of which impact roasting, brewing, and flavor potential. These methods aren’t arbitrary; they help ensure consistency, quality, and value in the green coffee supply chain.

In short, coffee beans are graded by two main methods: mesh size (from around 8 to 29, where bigger numbers mean larger beans) and growing altitude (seven tiers from as low as ~2,000 feet to above 4,500 feet). Size affects roast evenness; altitude often correlates with density and cup quality.

Grading by Mesh Size (Sieve Size)

Coffee beans are commonly graded by the size of the round holes they can pass through on a sieve or screen, measured in units called 'mesh' or 'sieve' numbers. The larger the number, the larger the hole—and the larger the bean that can pass through it. This system is especially common in Latin America and parts of Asia.

Mesh sizes are numbered typically between 8 and 29. Here’s the general breakdown:

• 8–10: Very small
• 12–13: Medium
• 15–16: Common commercial sizes
• 17–18: Large, often considered premium
• 19–20: Very large or 'extra large'
• 21–29: Extra-large to specialty-grade large

Flat beans (the normal bean shape) generally range from sieve 12 to 29, while peaberries (smaller, rounded beans that form when one seed in the coffee cherry doesn’t split) usually fall between 8 and 13. For example, an SC-19 refers to a sieve 19 flat bean. A designation like “19+” means the bean passes through a 19/64-inch sieve but may be retained on a higher mesh.

The actual measurement of each mesh number is based on fractions of an inch. For instance, a size “14” sieve allows beans smaller than 14/64 inches to pass, while “19+” indicates passage through 19/64 inches or larger. This unit is standard in international trade and among specialty roasters.

Grading by Altitude

Many coffee-growing countries classify beans by the altitude at which they’re grown, because elevation strongly influences bean density, sweetness, acidity, and overall cup quality. Generally, the higher the altitude, the slower the bean matures, leading to denser, more complex beans—hallmarks of specialty coffee.

Different origins use different terminology, but most follow a tiered altitude-based classification. Here’s a representative overview across key coffee-producing regions:

Higher-altitude grades such as S.H.B. (often called SHB or Strictly High Grown) are typically associated with brighter acidity, fuller body, and more pronounced flavors—traits sought after in specialty lots. Beans grown above 4,000 feet, depending on origin, may also command premium pricing due to lower yields and higher farming costs.

Regional Grading Standards Around the World

Each coffee-exporting country sets its own grading rules, resulting in a patchwork of classifications. Some focus on bean size, others on defect counts or growing conditions. Below are examples from major origins:

Africa: Kenya

Kenya uses a unique letter-and-number system:

• AA+ / AA / AA Plus-plus: Generally screen 17–18, the top grades
• AB: screen 15–16
• PB: Peaberry grade (small round beans)
• C, E: Lower commercial grades

Ethiopia

Ethiopian grading is defect-based. Using 300 grams of green coffee as a sample:

• Grade 1: 0–3 defects
• Grade 2: 4–12 defects
• …up to Grade 8: over 340 defects = substandard

South America: Colombia

Colombia classifies beans by screen size and type:

• Supremo: >17 sieve
• Excelso: 15–16.5 sieve
• UGQ (Usual Good Quality): 12–14 sieve
• Maragogype: 'Elephant bean' (very large flat bean)

Brazil

Brazil uses a numeric Type system (Type 2, 3, etc.) based on defect counts per 300g sample under different grading systems (New York/Le Havre). Type 2 allows 4–8 defects; Type 6 allows up to 151–225 defects.

Central America: Guatemala & El Salvador

Guatemala grades by altitude bands:

• Good Washed (GW): 700m
• Strictly Hard Bean (SHB): 1,600–1,700m
• Fancy Hard Bean (FHB): 1,500–1,600m
• …with several tiers in between (e.g., SH: 1,200–1,350m)

El Salvador uses:

• Central Standard (CS): 500–900m
• Strictly High Grown (SHG): >1,200m

Hawaii (Kona)

Kona coffee includes size-based grades:

• Extra Fancy: sieve 19, max 10 defects
• Fancy: sieve 18, max 16 defects
• Prime: no size rule, max 25 defects
• Caracoli No.1: sieve 10, max 20 defects

Jamaica

Jamaica Blue Mountain is graded as:

• Grade I: sieve 18
• Grade II: sieve 17
• Grade III: sieve 16

There’s also a separate Peaberry grade.

Indonesia

Indonesia grades mostly by defects in a 300g sample:

• Grade 1: 11 defects
• …up to Grade 6: 151–225 defects
• Also includes 4a (45–60 defects), 4b (61–80), etc.

Why Grading Matters

Grading ensures uniformity in bean size, which helps roasters achieve even development. It also signals origin quality, growing conditions, and market position. For specialty roasters and buyers, these grades offer a shorthand for expected cup profile, density, and potential roast behavior. Knowing how your beans were graded helps anticipate everything from roast curve to flavor notes.

Recommended FrontStreet Beans for Size & Altitude Lovers

Explore FrontStreet Coffee’s Ethiopia Huakui (washed, grown at 1,900–2,100m, known for citrus and floral notes), Jamaica Blue Mountain (graded Grade I, balanced and nutty with light acidity), and Kenya AA (high-altitude, complex and winey with berry tones). These beans reflect real-world grading by both size and altitude, offering distinct profiles tied to their origin standards. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.