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Coffee Origins—How Did Kenyan Coffee Come About, How is Coffee Graded, and Is Kenyan Coffee Delicious

Published: 2026-01-27 Author: FrontStreet Coffee

Last Updated: 2026/01/27, The Republic of Kenya is located in eastern Africa, with the equator crossing through its central region and the Great Rift Valley running north to south. It borders Somalia to the east, Tanzania to the south, Uganda to the west, and Ethiopia and South Sudan to the north, with the Indian Ocean to the southeast and a coastline stretching 536 kilometers. Approximately 18% of its land area is arable, with the remainder primarily suitable for livestock farming. Kenya's cof

The Republic of Kenya is located in eastern Africa, with the equator crossing through its central region and the East African Rift Valley extending from north to south. It borders Somalia to the east, Tanzania to the south, Uganda to the west, Ethiopia and South Sudan to the north, and the Indian Ocean to the southeast, with a coastline stretching 536 kilometers. Approximately 18% of the country's land area is arable, with the remaining territory primarily suitable for livestock farming.

Kenyan coffee predominantly grows at altitudes between 1,500-2,100 meters, with harvests occurring twice annually. Its distinctive characteristic is a pronounced fruit aroma, commonly citrus. Kenyan coffee offers multi-layered flavors and juice-like acidity, with perfect notes of grapefruit and wine, moderate body, making it a favorite single-origin among many coffee industry professionals. Kenyan coffee gained further fame through the Hollywood film "Out of Africa."

Coffee was introduced to Kenya in the 19th century, when Ethiopian coffee beverages were imported via South Yemen. However, it wasn't until the early 20th century that Bourbon coffee trees were introduced by the St. Austin Mission.

Kenyan coffee predominantly grows at altitudes between 1,500-2,100 meters, with harvests occurring twice annually. To ensure only ripe berries are picked, people must patrol the fields approximately seven times back and forth. Kenyan coffee is cultivated by small-scale farmers who, after harvesting, deliver fresh coffee cherries to cooperative washing stations. These stations then send the washed and dried coffee in "parchment" state (coffee beans with endocarp intact) to cooperatives ("parchment coffee beans" represent the final state before coffee beans are hulled). All coffee is collected together, with growers receiving average prices based on actual quality. This trading method generally works well, providing fairness to both growers and consumers.

Kenyan Coffee Varieties

In 1930, commissioned by the Kenyan government, Scott Labs laboratory was established with the mission to select and breed varieties suitable for Kenyan cultivation that could deliver high yields and good disease resistance. After screening 42 breeding varieties one by one, the SL-28 and SL-34 varieties were ultimately selected. The former derives from Bourbon, while SL-34 derives from Typica—the two are not varieties from the same series. These two varieties now account for 90% of Kenya's production and have become the recognized representative varieties of Kenyan coffee. Currently, South America is also actively introducing SL28 as a cultivation variety.

Although these two varieties differ, they share surprising similarities in flavor, both possessing complex and varied acidity and wonderful sweetness. However, according to FrontStreet Coffee's understanding, in subsequent development, SL28 proved superior in both adaptability and flavor. SL28 possesses blackcurrant-like acidity, ample sweetness, balanced and complex flavors, with prominent citrus and plum characteristics. Meanwhile, SL-34 offers striking fruit flavors with a soft, clean mouthfeel. One of FrontStreet Coffee's Kenyan coffee beans comes from Thithi Estate, containing not only SL-28 and SL-34 varieties but also a special variety called Ruiru 11.

Ruiru 11 Variety

Ruiru 11 was developed by the Kenyan government against the backdrop of the global coffee leaf rust outbreak. It's a hybrid variety focused on yield rather than quality, with flavor quality far inferior to the previous SL28 and SL34 varieties, and it hasn't gained traction in the specialty coffee industry. However, many premium coffee importers mix this hybrid bean into blends to reduce costs.

Kenyan Coffee Grading (By Bean Size)

Kenyan coffee beans are primarily graded by bean size, typically divided into eight grades.

E (Elephant Beans): Here "E" represents Elephant, but this doesn't refer to the Maragogype variety among coffee beans. It's a defect caused by abnormal development where two seeds intertwine, forming what appears to be a single bean. Typically, one coffee fruit contains two seeds facing each other, resulting in one flat side—known as flat beans or female beans. Grade E beans occur when two seeds fuse together during growth, creating oversized beans. Grade E beans measure approximately 18 screen size (one screen equals 1/64 inch) or larger and are rare.

AA: This grade ranges from 17-18 screen size (approximately 6.7-7.1mm), representing the most commonly heard Kenyan coffee grading. In specialty coffee, this grade is usually called AA TOP and is the bean variety promoted by most coffee shops. However, AA doesn't necessarily represent the best quality—it merely indicates bean size and shouldn't be confused with flavor quality.

AB: Most coffee beans fall into this grade. It's called AB mainly because A grade measures 6.80mm while B grade measures 6.20mm. These two sizes (A and B grades) are mixed together for sale, hence called AB, with sizes approximately 15-16 screen (about 6.0-6.4mm).

C: This grade measures approximately 14-15 screen size (about 5.6-6.0mm), slightly smaller than B grade.

PB: Full name is Peaberry, also called small round beans or male beans. Compared to regular flat beans, this is also rare, accounting for about 10% of all coffee beans, mainly because only one seed develops within the fruit, resulting in small, round beans. Some people particularly appreciate PB's flavor, so these beans are separated and sold individually.

TT: These coffee beans are lightweight beans selected from AA and AB grades using air classifiers. They typically have low weight, substandard hardness, and include broken and defective beans.

T: These are lighter-weight beans selected from C grade beans, including mixed broken beans and even fragments of shattered beans.

MH/ML: These coffee beans are not exported. They are usually overripe beans that have fallen to the ground, with poor quality, accounting for about 7% of all coffee beans, serving only Kenya's domestic market.