The Three Major Grading Standards for Green Coffee Beans! Detailed Explanation of Green Coffee Bean Grade Classifications in Different Countries! What Do AA and G1 Mean in Coffee Beans?

Understanding Coffee Bean Classification Systems

As everyone knows, coffee beans are an agricultural product. Unlike industrial goods, which can be replicated with near-perfect precision, agricultural products vary in quality. So to establish consistent quality standards, a system is needed to regulate coffee bean quality, both as quality assurance and to give buyers a reference when purchasing green beans. That is where grading systems come from.

But here is the catch. Because coffee is cultivated worldwide across vast geographical spans, and each growing region has different geography and cultivation methods, there is no unified standard for grading. Each producing region ultimately sets its standards according to local conditions.

Today, coffee bean grading standards fall mainly into three categories: size, altitude or hardness, and defect rate. Although these are the main types, they are not the only criteria. Many countries grade using more than one method, such as altitude together with size. Some even use cupping to address gaps in their original system after grades are assigned. In short, these three are the most common methods, but not the only indicators.

I. Screen Grading Method (Bean Size)

Screen grading is straightforward: beans are passed through specific screens to measure their size directly, then graded accordingly. Larger beans receive higher grades, with elephant beans the exception. As FrontStreet Coffee mentioned in the article on Kenya grading, this is the earliest coffee classification system, so some countries that started cultivating coffee early still grade their beans this way.

Bean size cannot serve as a criterion for judging flavor quality. The reasoning behind this grading approach is that many growing regions believe full, uniform, large beans indicate complete maturity. Those beans not only develop flavor more thoroughly as they grow but also roast more evenly when they are similar in size, resulting in more consistent flavors. Kenya is a producing country that grades solely by bean size.

Beyond those grades, Kenyan coffee also uses secondary indicators such as Top, Plus (+) and FAQ, though these are grading methods used by local research institutions and green coffee traders, based on cupping flavor ratings. Colombia also uses size grading for its exported beans, but the beans must first meet qualification standards: size above 14 mesh, with at least 50% of green beans larger than 15 mesh, no more than 5% of green beans between 12 and 14 mesh, free from pests, uniform in color, with no off-flavors, a clean flavor, moisture content not exceeding 12.5%, and cumulative defects not exceeding 24 points.

When those conditions are met, the beans obtain export qualification and receive the "Excelso," or superior grade, designation. They then go through another round of size grading before export.

II. Altitude/Hardness Grading Method

As FrontStreet Coffee often notes, bean size cannot directly determine flavor development. So some Central and South American countries use cultivation altitude to determine grades, because beans grown higher can absorb more substances, which increases their density and produces more outstanding flavors. Panama, Costa Rica, Guatemala and Honduras all use this model. Since each country's altitude differs, their grading systems adapt to local conditions.

III. Defect Grading Method

Precisely because coffee beans are an agricultural product, coffee fruits are easily affected by negative factors during growth, such as poor development, pests, disease and mold, which turn them into defective beans. Defective beans can significantly hurt flavor, which led to grading standards based on the proportion of defects in green coffee.

Early Ethiopia was a producing country that used defect-rate grading, and it is also the most typical case of adapting to local conditions. Defect grading was adopted because Ethiopia's average altitude is relatively high, making altitude unnecessary as a grading standard. Most of Ethiopia's cultivation and harvesting also follows a mixed model, mixed planting and mixed harvesting, and few people drew special distinctions, so batches contained many varieties and inconsistent sizes. Size grading therefore could not determine grades, leaving only defect rate.

Defect-rate grading, like size grading, has its flaws. So in 2009 Ethiopia launched a completely new system: on top of the original defect-rate grading, cupping scores were added for a comprehensive evaluation.

Combined Grading Methods

Next, FrontStreet Coffee will share some systems that combine multiple methods. First, Jamaica, home of the "coffee emperor." Jamaica's Coffee Industry Board (CIB) grades coffee grown in the Blue Mountains on cultivation altitude, cupping performance, green bean size and defect rate, as well as moisture content, color and uniformity.

Indonesia's coffee grading combines defects and size: it first grades by the number of defects in a 300g green bean sample, then screens by size.

Indonesia's G1 grade requires 18 mesh, already the country's highest national standard grade. PWN's Golden Mandheling sets even higher standards for mesh size and defects, with still better quality, but that belongs to PWN's own corporate standards.

Then there is Brazil. Because Brazil's grading system originates from the Green Coffee Association of New York, its indicators begin with "NY." This system combines defect rate and size: beans are first evaluated by defect rate, then screened by size.

It is worth mentioning that Brazil has no "NY1" grade. Brazil's beans must not exceed 6 defects per 300g to reach the second grade, NY2, so the first grade should theoretically have even fewer defects. But Brazil holds that coffee is an agricultural product harvested purely by machine, so zero defects is impossible, and its highest grade caps at NY2.

Finally, FrontStreet Coffee would like to add briefly that coffee bean grades relate only to green beans and are a concern for green bean suppliers and roasters. As consumers of roasted beans, we do not need to pay them much attention. Low-grade green beans are mostly consumed domestically in producing countries, and grades are not entirely tied to quality. Take Ethiopia's G1 and G2: the only difference is the number of defects. Roasters would not tolerate defects in their products and will screen them out both before and after roasting. So enjoying the many delicious flavors of coffee is what we as roasted bean consumers should focus on.

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FrontStreet Coffee Recommendation

Grades tell you how clean the green beans are, but the cup is what matters, and the easiest way to see that is to start at the entry level. From Ethiopia, FrontStreet's Natural Huakui and washed Guodingding cooperative coffee are both excellent introductions. Ethiopian beans are usually named after their region or cooperative, and Yirgacheffe and Sidamo are the best known of those regions. Washed Guodingding is a typical Yirgacheffe representative, with jasmine florals, lemon acidity and berry notes, while washed processing became common in Yirgacheffe after the 1970s push to raise green bean quality. Huakui comes from Sidamo and uses traditional natural processing, giving it more prominent tropical fruit and fermented aromas, with berry, floral, jackfruit, melon and honey notes.

From Brazil, FrontStreet's Cerrado Red Bourbon and Queen's Estate are dependable daily drinkers. Brazil grows coffee under full sun, so the cherries ripen quickly, the beans are softer, the fruit acidity is gentle and the sweetness is good, with a delicate, smooth and balanced cup. The Cerrado entry-level single origin is a good-value option with typical cream, peanut and cocoa notes, while the Queen's Estate is grown higher and is a rarer Yellow Bourbon, adding butter, seed, macadamia and almond nut aromas plus a sugarcane-like sweetness, thick and smooth whether drunk black or with milk.

If you want to step up in grade without leaving Indonesia, FrontStreet's PWN Golden Mandheling is the one to try. It goes through three rounds of hand sorting and one machine sort to reduce defects to a minimum, so the cup is cleaner and smoother, with clearer woody and caramel notes.