How does coffee classification and grading work in Kenya?

Kenyan coffee is sorted into eight grades based on bean size and screening source. The rare E grade, known as Elephant beans, sits at the top, followed by AA, AB and the smaller PB, C and TT lots, with MH and ML reserved for domestic sale. Each tier carries different size, density and quality expectations that shape how the coffee is traded.

The system reflects Kenya's growing conditions. The equator crosses the country, the East African Rift Valley runs north to south, and most farmland sits on plateaus averaging about 1,500 meters. Coffee arrived in the 19th century, while Bourbon coffee trees came through the St. Austin Mission in the early 20th century. Bright fruity aroma and juicy acidity remain the country's signature.

Kenyan coffee is renowned worldwide for its bright fruity aromas and juicy acidity, and is a beloved favorite among many coffee enthusiasts. But do you know how Kenyan coffee beans are graded? This article will guide you through the eight grading levels of Kenyan coffee—from the rare E-grade Elephant beans to the MH/ML grades reserved for domestic sale only—analyzing each tier's bean size, screening source, and quality characteristics one by one. It will also introduce Kenya's coffee-growing history, main producing regions, and harvest seasons, helping you gain a more comprehensive understanding of this African specialty coffee-producing country's grading system. Front Street Coffee also recommends noteworthy Kenyan bean varieties in this article.

Kenya borders Ethiopia, the birthplace of coffee, and its coffee enjoys an extremely high reputation internationally, with industry insiders almost unanimously ranking it among their favorite categories. The reason is that a cup of high-quality Kenyan coffee encompasses nearly everything people expect from good coffee—pleasing aromatics, balanced and appealing acidity, uniform and plump beans, and outstanding fruity notes. Its flavor is highly distinctive, and it is difficult to find a similar substitute.

The most prominent label of Kenyan coffee is its bright fruity aroma, and when tasting, it's worth paying attention to how it performs in the mouth. Citrus-like aromas are the most commonly occurring type. Overall, Kenyan coffee is richly layered, with juicy acidity and a pleasant body, often capturing grapefruit and wine-like flavors.

Coffee was introduced to Kenya as far back as the 19th century, initially brought to the region by South Yemen from Ethiopia as a coffee beverage. However, Bourbon coffee trees were not introduced for cultivation until the early 20th century through the St. Austin Mission.

Kenyan Coffee Cultivation

Kenya is located in East Africa, with the equator passing through the middle of the country and the East African Rift Valley running north to south. To its east lies Somalia, to the south Tanzania, to the west Uganda, to the north Ethiopia and Sudan, and to the southeast the Indian Ocean. The country's terrain is predominantly plateau, with an average elevation of about 1,500 meters. Mount Kirinyaga (Mount Kenya) in the center, at 5,199 meters, is Africa's second-highest peak, with its summit covered in snow year-round.

As a tropical producing region, Kenya has two rainy seasons per year, allowing for two coffee harvests. About 60% of production is concentrated from October to December, with the remaining 40% from June to August. Coffee farms are mainly distributed in the volcanic soil zone at elevations of 1,600 to 2,100 meters, from the capital Nairobi to the areas around Mount Kenya. This elevation range is conducive to flavor development: lower temperatures in the mountains cause coffee cherries to grow slowly, allowing aromatic compounds to fully form, fruit acidity to become more pronounced, and beans to be denser. This fertile, crescent-shaped coffee-growing belt is the core source of Kenyan specialty beans.

Kenya's coffee-producing regions are mainly divided into six major areas: Thika, Kirinyaga, Mt. Kenya West, Nyeri, Kiambu, and Muranga. The six regions share the same harvest periods, with the main season from October to December and the secondary season from June to August.

So how exactly are Kenyan coffee beans graded? The grading is primarily based on bean size, typically divided into eight levels.

E Grade (Elephant Bean): The letter E comes from Elephant, but it is not the same concept as the Maragogype variety of coffee. E-grade beans are the result of abnormal development, where two seeds become intertwined, appearing externally as a "single bean," and are essentially a defect. Normally, a coffee cherry contains two seeds that press face-to-face, so each has one flat side; these are called flat beans or female beans. E-grade beans, however, are two seeds that have fused together during growth, forming an oversized bean. They are typically above 18 screen sizes (1 screen size equals 1/64 inch), and production is extremely rare.

AA Grade: This grade has a bean size of approximately 17 to 18 screen sizes (about 6.7 to 7.1 mm), and is the most prominently featured in Kenyan coffee grading. In the specialty coffee world, it is often given the title AA TOP, and is also a flagship product promoted by many coffee shops. However, it should be noted that AA only represents bean size and does not directly equate to the best flavor.

AB Grade: Most coffee beans fall into this grade. The name comes from A-grade (6.80 mm screen size) and B-grade (6.20 mm screen size) beans being mixed and sold together, hence the combined name AB, with sizes of approximately 15 to 16 screen sizes (about 6.0 to 6.4 mm).

C Grade: Bean size ranges between 14 and 15 screen sizes (about 5.6 to 6.0 mm), smaller than B grade.

PB Grade: Full name Peaberry, also called round bean or male bean. Compared to the common flat bean, PB is also relatively rare, accounting for about one-tenth of total coffee beans. It occurs when only one seed develops within the cherry, resulting in a small, round bean. Some enthusiasts particularly favor the flavor of PB, so it is sometimes sorted out and sold separately.

TT Grade: These beans are lightweight beans removed from AA and AB grades by air separation machines. They are typically lighter in weight, fail to meet hardness standards, and often have cracks and defects.

T Grade: Lighter beans screened from C-grade beans, mixed with broken beans and even fragments.

MH/ML Grade: This grade is not for export. These are mostly overripe beans that have fallen to the ground, of poor quality, accounting for about 7% of total coffee beans, and are supplied only to the domestic Kenyan market.

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