Detailed Introduction to Coffee Bean Grading Systems Worldwide - Ethiopian and Kenyan Coffee Bean Grading Standards

A friend asked FrontStreet Coffee, "Why do some coffee beans have grades like AA, some like G1, and others like SHB? These letters seem to have no pattern—how can I know which grade is higher and which is lower?"

Why is grading necessary?

When you walk into a fruit store, you often see the same type of fruit displayed in two sections with the same product name but vastly different prices. Upon closer inspection, you'll find that the more expensive section contains larger, better-looking fruits, while the cheaper section has smaller, less aesthetically pleasing ones.

Agricultural products cannot achieve the same standardization as industrial products—variation in quality is normal. Therefore, grading standards were established to regulate coffee bean quality. They also provide a value reference for green bean traders when purchasing coffee beans.

As the friends mentioned earlier, AA, G1, and SHB are all grades of green coffee beans, but these grades come from standards set by different coffee-producing countries.

Why not adopt a unified green bean standard?

Some friends might wonder why coffee bean grading standards aren't unified. This is because each producing country has different geographical environments and cultivation patterns, resulting in each country developing green bean grading systems based on their national conditions. The adopted standards are adapted to local circumstances and generally fall into categories such as defect rate, bean size, growing altitude, and cupping quality.

Ethiopia: Grading Based on Defect Rate

Ethiopia's grading system is primarily based on the number of defective beans per 300g of green beans. For example, G1 allows no more than 3 defective beans per 300g of green beans, while G2 allows 4-12 defective beans per 300g, and so on.

This is because Ethiopia's coffee cultivation model is relatively primitive, dominated by smallholder farming, and the rough processing methods in earlier years resulted in extremely inconsistent coffee bean quality. Therefore, grading is based on the number of defects—coffee batches with fewer defects receive higher grades and naturally command higher prices.

Ethiopia is home to many wild coffee varieties, locally generally referred to as heirloom varieties. Among these complex and numerous varieties, some have larger coffee beans, some have smaller ones, and some varieties, despite having smaller beans, exhibit excellent flavor performance. Therefore, using green bean volume for classification is impractical. Ethiopia's terrain consists of high plateaus with high and relatively flat altitudes, making altitude-based grading unsuitable as well.

Kenya: Grading Based on Bean Size

The most representative country that uses coffee bean size as its grading standard is Kenya. Although Kenya has numerous coffee grades, consumers actually only encounter beans graded as AA, AB, and PB. Because Kenya commonly cultivates the SL28 and SL34 coffee varieties, theoretically, the larger the coffee beans, the better the quality.

The PB grade is quite special—PB stands for Peaberry, meaning "round bean," which occurs when a coffee cherry contains only one seed. Although its screen size is around 14-15, due to its special shape, it can be separated and sold at AA prices (otherwise, it would be classified as Grade C).

Central America: Altitude-Based Grading

Producing countries that use altitude as the standard for coffee bean grading are mainly concentrated in the Central American region. Here, towering mountains and large altitude ranges prevail. Additionally, the higher Arabica coffee beans are grown, the harder their texture and the better their flavor. At the same time, the coffee-growing altitudes within these major producing countries are not entirely the same, so these countries have developed different grading standards based on their national conditions.

For example, Costa Rica, Guatemala, and Panama use hardness to describe grades, with SHB being the highest grade in all three countries. However, their altitude definitions for SHB differ slightly. Costa Rica defines coffee beans grown above 1,200 meters as SHB, Guatemala defines those grown above 1,350 meters as SHB, and Panama defines those grown above 1,400 meters as SHB.

Multi-Factor Grading Systems

Some producing countries use multiple factors as the basis for grading standards. For example, Jamaica's coffee grading system uses both bean size and altitude as criteria. According to different altitudes, it's divided into Blue Mountain Coffee, High Mountain Coffee, and Jamaica Prime Coffee. Based on bean size, it's classified as NO.1, NO.2, and NO.3.

Brazil's green coffee bean standards are based on defect count, bean size, and flavor evaluation. For example, a bag of green coffee beans might be labeled "NY2 SC-17/18 Good cup."

The preceding NY2 indicates the defect count grade—Brazil's highest grade is NY2, with no NY1 grade existing.

SC-17/18 indicates that the green beans in this bag are size 17-18 screen. "Good cup" refers to the coffee's cupping quality. Cupping quality grades can be divided into "Fine cup, Good cup, Fair cup, Poor cup, Bad cup."

Therefore, the criteria used by each country's coffee bean grading standards are quite different. In other words, there is no unified standard for judging whether beans are good or bad, making it impossible to use green bean grades for cross-country comparisons. Moreover, these grading standards target the state of green beans and serve more as a reference for green bean traders when purchasing coffee beans.

When it comes to the roasted bean market, the influence of these grades is even diminished, as everything is uniformly AA, G1, SHB—these highest grades. At most, you might only encounter the top two grades of the grading standards; the lower grades are rarely seen. As for what are considered good and bad beans in the roasted bean market, their price differences at origin are not as significant as people might imagine.

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