Why Does Ethiopia Grade Green Coffee Beans by Defects?

Ethiopia grades green coffee beans by defect rate rather than altitude or bean size. G1 and G2 sit at the top of that scale, and the gap between them shows up in the raw bean, in roasting behavior and in the cup. Central America mostly grades by altitude and Kenya by bean size, so standards vary by origin.

Coffee is an agricultural product, and quality cannot be made fully uniform, which is why grading systems exist. They let exporters sort lots and give buyers a reference when purchasing green coffee bean lots. Packaging often prints grade labels so consumers can read the export convention at a glance.

As an agricultural product, coffee beans vary in quality, which is why grading systems have become an important means of standardizing quality and guiding green bean purchasing. However, grading criteria are not uniform across producing regions worldwide—Central America mostly grades by altitude, Kenya by bean size, while Ethiopia uses defect rate to determine grades. Why does Ethiopia take this unique route? What substantial differences actually exist between the G1 and G2 grades? This article, from the perspective of Front Street Coffee, traces the evolution logic of Ethiopia's grading system, and through visual comparison of Yirgacheffe G1 and G2 green beans, roasting performance, and cupping evaluation, reveals the true meaning behind grade labels one by one, helping coffee enthusiasts view the bean grade issue more rationally.

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Green coffee beans are ultimately an agricultural product, and agricultural products, unlike industrial goods, cannot achieve completely consistent quality—there are simply too many variables affecting their quality. To prevent beans of varying quality from being lumped together, a grading system is needed to make standardized judgments about coffee bean quality. At the same time, grade labels also provide green bean buyers with a reference when selecting raw materials.

When we purchase roasted coffee beans, most packaging bags also print grade information—this is actually merchants following the labeling conventions of the export end, allowing consumers to intuitively understand bean grades. However, attentive observers may notice that different producing regions use different grade labeling methods. The reason is that there is still no unified global standard for coffee bean grading.

Some regions grade based on the altitude at which coffee is grown, as is the case for most Central American origins; some regions look at bean size, with Kenya as a typical example; and some regions use defect rate to determine grade, which is the category Ethiopia belongs to. Geographical conditions and cultivation methods vary greatly from country to country, so green bean grading is always formulated in accordance with each country's own circumstances. Speaking of which, Front Street must elaborate on Ethiopia's grading system.

What exactly does grading by defect rate mean?

Ethiopia is the birthplace of coffee, and thousands of coffee varieties within its borders have yet to be systematically identified. To prevent outsiders from continuously stealing these unknown variety resources, the Ethiopian government collectively calls them "Heirloom" for protection purposes. So when we buy a bag of Ethiopian heirloom coffee beans, upon opening the package we find that bean sizes are uneven—tall, short, fat, and thin each make up a certain proportion.

Ethiopian coffee trees are mainly in wild and semi-wild states, scattered across various regions of the country. Each harvest season, surrounding farmers act collectively to pick ripe cherries scattered in fields and forests. In the same plot of land, dozens of different coffee tree varieties may be growing.

Although these coffee beans come from different varieties, farmers are not obliged to separate them. As long as they pick the ripe red cherries and sell them to the processing station, they can receive corresponding payment.

The processing station also does not differentiate the bean varieties collected from different surrounding farmers, but instead mixes them directly for unified processing. It is precisely this relatively rough harvesting and processing method that causes the uneven bean sizes. It is worth mentioning that some beans, despite being small, have quite outstanding flavors. Therefore, Ethiopia cannot rely on size to grade coffee beans.

In addition, Ethiopia as a whole has high altitude and relatively flat terrain, with coffee basically grown at similar elevations, which also makes altitude unable to serve as a basis for distinguishing grades. Ultimately, the Ethiopian government decided to classify grades by the defect rate content of the beans.

Of course, grading solely by defect rate inevitably "wrongly penalizes" many coffee beans with excellent flavor. Therefore, after 2009, the Ethiopian government revised the grading system, no longer determining grades only by defect rate, but conducting a secondary evaluation combining cupping and bean appearance on the basis of defect rate screening.

So what exactly is the difference between G1 and G2 beans?

Great, today's case is the familiar Yirgacheffe again~~ The green beans in the image below are Yirgacheffe of G1 grade and G2 grade respectively, both washed processed. Let's first look at their appearance to see what differences there are!

As can be seen, the G1 grade Kochere green beans are noticeably plumper than the G2 grade ones, and their color is more uniform. Upon closer observation, you can also find that G2 has more defective beans than G1—of course, this is expected! Next, let's screen out the defective beans, proceed with roasting, and see what differences appear after roasting!

Roasting complete! Due to different bean sizes, there is a slight difference in color value between the two. Front Street chose a light roast—light roasting preserves more floral and fruity notes, fully showcasing the flavor characteristics of Yirgacheffe.

Brewing parameters: 15g coffee grounds; 1:15 coffee-to-water ratio; EK43 at setting 10 grind; 92°C water temperature; V60 dripper; three-pour brewing method.

Step one, bloom with twice the coffee grounds' weight in water for 30 seconds; after blooming is complete, pour the second stage of 120ml hot water in a steady small stream, circling in large circles at a uniform speed; when the water level is about to reach the bottom, pour the final stage of hot water (75ml) in a steady stream, circling in small circles at a uniform speed; then simply wait for the drip to finish.

Through Front Street's tasting, it can be found that the G2 grade Yirgacheffe presents very classic regional flavors: lemon, white florals, citrus acidity, and a green tea-like finish. The G1 grade Yirgacheffe, on this basis, has brighter acidity, a cleaner mouthfeel, and a slightly longer aftertaste! But without direct comparison, the differences between the two are actually not very easy to detect.

In summary, G1 and G2 Yirgacheffe do not differ much in flavor profile—G1 simply has a better mouthfeel than G2, which is the main difference brought by grade. It should be understood that grades are mainly for green bean buyers' reference when purchasing; once they enter the roasted bean market, the influence of these grades becomes very limited. After all, cafes by default purchase high-grade, high-quality coffee beans, and apart from the top two grades in the grading standard, lower grades are almost impossible to find on the market~ So everyone need not worry too much about bean grade issues~

The above content is compiled by CoffeeHunters, a coffee news website.