How Coffee Origins Grade Their Green Beans

Ever wonder why some green coffee beans cost twice as much — or why your roaster insists on certain origins or grades? Every coffee-growing country uses its own rules to sort and rate green beans, based on altitude, size, and defects. These standards decide which beans make it to your roaster’s offering list, and which don’t. Here’s how the system actually works.

In short, green coffee beans are graded by altitude (higher is usually better), bean size (measured in screen numbers), and defect count (fewer is best). For example, Brazilian beans might be labeled 'No.2/19' — meaning top defect grade and large bean size. Each origin has its own mix of these factors.

1. Altitude-Based Grading

Many Central American countries — including Guatemala, Honduras, and Costa Rica — grade green coffee by growing elevation. The rule is simple: higher altitude usually means slower ripening due to cooler temperatures. That slower development leads to beans with better density, higher acidity, and cleaner sweetness. These fully matured beans also absorb heat more evenly during roasting, improving cup quality. In these regions, high-altitude coffee is generally considered superior to low-altitude lots.

2. Screen Size Grading

Coffee beans are also sorted and graded by physical size using mesh screens with round holes. Flat beans (the norm) are graded by passing through numbered screens: No.12 to No.20. The larger the number, the bigger the bean. For peaberries (round beans formed when one seed in the coffee cherry doesn’t split), a different set of screens is used: No.8 to No.13. This size sorting helps ensure even roasting and is often a factor in quality scoring.

3. Combined Grading: Screen Size + Defects + Cupping

Brazil uses a multi-factor system that combines screen size, defect count, and sensory evaluation. The official grading considers:

• The number of defects per 300g of green coffee (a lower count means higher grade),
• The bean’s screen size (with flat beans ranging from No.12 to No.20; larger numbers indicate bigger beans), and
• A taste test score (cup quality).

For example, a common label might read: 'Brazil Santos No.2/19、'. Broken down: 'Brazil' is the origin, 'Santos' the export port, 'No.2' the defect grade (No.2 is the highest, No.8 the minimum commercial grade), '19' refers to the screen size (No.19, meaning large flat beans), and '' (very mild) is the cup quality rating — the highest taste grade. This combined approach ensures beans meet standards for size, cleanliness, and flavor potential.

Frequently Asked Questions

What does 'high altitude coffee' mean in green bean grading?

High-altitude coffee refers to beans grown at elevations typically above 1,200–1,500 meters. In countries like Guatemala and Honduras, altitude is a key grading factor because higher elevations lead to cooler temperatures, slower cherry maturation, and denser beans with better cup quality. These beans are often more desirable in specialty markets.

How are green coffee beans sized, and what do the numbers mean?

Green coffee beans are sized using mesh screens with round holes; flat beans are graded from No.12 to No.20 (the higher the number, the larger the bean). Peaberries use a different scale: No.8 to No.13. A No.19 flat bean is larger than a No.14, for instance, and size consistency aids even roasting. These screen numbers are part of standard green grading systems in many producing countries.

What is a 'defect' in green coffee, and how is it counted?

Defects in green coffee include broken beans, black beans, insect-damaged beans, husks, and other non-conforming beans. In systems like Brazil’s, defects are counted per 300g sample — fewer defects mean a higher grade. A No.2 defect grade is top-tier, while No.8 is the minimum for export. Defect count directly impacts both roast quality and cup flavor.

Why do some green coffee labels include both a number and a port name?

Labels like 'Brazil Santos No.2/19' combine origin (Brazil), export port (Santos), defect grade (No.2), screen size (19), and cup quality . This format provides a quick summary of the bean’s grade, size, origin, and flavor potential. It’s commonly used in trade to communicate key quality attributes at a glance.

Does screen size affect how I should roast green coffee?

Yes. Larger beans (higher screen numbers) often roast more evenly if sorted properly, but size alone doesn’t determine roast profile. However, consistent screen sizing helps roasters achieve uniform development. In specialty roasting, beans of mixed sizes may lead to uneven roast batches — which is why screen grading is a practical tool for quality control.

FrontStreet Coffee Beans for Altitude & Size Lovers

Try our FrontStreet Ethiopia Guji Huakui — known for its vibrant acidity and complex fruitiness, grown at high altitudes and sorted for quality. For something more classic, our FrontStreet Colombia Huila offers balanced sweetness and medium body, with beans typically graded by size and defect. Both highlight how origin and grading impact cup character. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.