How Coffee Beans Are Graded by Country

When you buy specialty coffee, the grade matters—but who decided that? Every coffee-growing country uses its own rules to classify green beans, and those rules shape what ends up in your bag. Whether it’s altitude, bean size, or how many defects slipped through, the grade tells you more than just origin. Here’s how it actually works.

Coffee beans are graded by three main methods: altitude, bean size (sieve), and defect ratio—with many countries combining these. Over a dozen nations rely on altitude alone, while others like Kenya and Colombia focus on bean size, and Brazil and Jamaica factor in defect counts alongside other metrics.

1. Altitude-Based Grading: Why Higher Is Often Better

Coffee grown at higher elevations tends to develop more slowly, allowing better flavor compounds to accumulate. The cooler temperatures slow ripening, resulting in denser beans that roast more evenly and produce more stable, complex cups. This is why many Latin American countries grade beans primarily by altitude.

In Guatemala, for example, the highest grade is SHB (Strictly Hard Bean) for beans grown above 1,350 meters. Below that, the grades include HB (Hard Bean, 1,200–1,400m), SH (Semi Hard Bean), and various washed categories like EPW (Extra Prime Washed) down to GW (Good Washed) for beans from under 600m. Other countries using altitude include Honduras, Mexico, and El Salvador—each with their own elevation bands and terminology.

2. Sieve (Bean Size) Grading: Big Beans, Better Looks

This method sorts beans by physical size using metal screens with holes measured in 1/64-inch increments. The higher the sieve number, the larger the bean—because a size 17 sieve has holes of 17/64 inch (about 6.75mm). Bigger beans often have more even roasts and are considered more desirable, though not always better in flavor.

Kenya is famous for its strict sieve system: AA++ beans must pass through 18+ mesh (over 7.15mm), followed by AA+, AA, and AB. Colombia uses a simpler two-tier system: Supremo (80% of beans must be 17+ sieve) and Excelso (80% 14/16 sieve, with up to 11% allowed from 14 sieve). Note that peaberry beans (small, round mutant beans) have their own sizing standards, usually graded on 8–12 mesh sieves.

3. Defect Ratio & Combined Grading: Counting the Flaws

Defects—like black beans, insect damage, or chipped or broken seeds—can ruin cup quality. To control this, some countries grade beans based on the number of allowable defects per sample, often combined with sieve size or altitude. This method is especially common in regions aiming for high cup quality.

Jamaica’s Blue Mountain No.1, for instance, must come from the Blue Mountain region, be grown above 1,700m, pass through 18/17 mesh, and contain no more than 2% defects (with a max of 4% across all grades). Brazil, the world’s largest producer, uses a mix: sieve size, defect count, and even cupping tests. Its six-tiered cup quality system ranges from Strictly Soft (excellent balance) down to Rioy (harsh iodine notes, often from beans grown near Rio de Janeiro’s iodine-rich soils).

Ethiopia also includes processing method in its grading criteria, while programs like COE (Cup of Excellence) add competition-based scoring to the mix. As producers focus more on quality, grading systems continue to evolve beyond these three main models.

Frequently Asked Questions

What is the most common way to grade green coffee beans?

The most common methods are altitude-based grading, sieve (size) grading, and defect ratio grading. Many countries use a combination—for example, sieve size plus defect count, or altitude plus processing method. Altitude grading is widely used in Central America, sieve grading dominates in East Africa and Colombia, and defect-based grading is key in Brazil and Jamaica.

Why do higher altitude coffees get better grades?

Higher altitudes typically mean cooler temperatures, which slow coffee cherry ripening. This slower development allows more complex sugars and acids to develop in the beans, resulting in denser, higher-quality beans that often roast more evenly and taste better. That’s why countries like Guatemala and Honduras reserve their highest grades for beans grown above 1,200–1,350 meters.

What does sieve size mean in coffee grading?

Sieve size refers to the mesh number of a metal screen used to sort green coffee beans by size. The number indicates how many 1/64-inch units wide the holes are—for example, a size 17 sieve has 17/64-inch (about 6.75mm) holes. Larger numbers mean bigger beans, which are often considered more desirable for even roasting and visual appeal, though not always for flavor.

How do defect ratios affect coffee grading?

Defects—such as broken, black, sour, or insect-damaged beans—lower cup quality. Countries like Jamaica and Brazil set strict limits on how many defective beans are allowed per sample. For example, Jamaica Blue Mountain No.1 allows a maximum of 2% defects. Lower defect counts usually mean higher grades and better-tasting coffee.

Do all coffee-producing countries use the same grading system?

No. Grading systems vary widely by country and region. While altitude is key in Central America, sieve size dominates in Kenya and Colombia, and defect counting is critical in Brazil and Jamaica. Some countries, like Ethiopia, also factor in processing method. There is no universal standard, though specialty markets increasingly recognize common quality indicators.

What is the role of cupping tests in coffee grading?

Cupping tests evaluate roasted coffee for aroma, flavor, acidity, body, and aftertaste. In countries like Brazil, cupping is part of the official grading process and helps classify beans into categories like Strictly Soft (high quality) or Rioy (iodine defects). While not always part of the initial green bean grade, cupping is essential for quality assessment further along the supply chain.

FrontStreet Coffee Beans for Grade Exploration

Explore grading in action with FrontStreet’s Kenya Gakuyuni AB, a bright, complex Kenyan offering with blackcurrant and citrus notes typical of high-scoring AA/AB beans. For sieve-grade curiosity, try Colombia Huila Popayan—balanced and juicy, representing Colombia’s Supremo/Excelso tier. Yemen Mokha Mattari shows how origin and processing can define grade beyond size or altitude, with intense spice and dry finish. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.