How Does the Kenya Coffee Grading System Work?

Kenya's coffee grading system sorts beans by screen size and cup quality, and the Thika area in Kiambu is one of the country's established growing zones. Coffee there is cultivated mainly on volcanic soils at 1,600 to 2,100 meters, where the slow cherry ripening produces the dense beans and bright fruit acidity that Kenyan coffee is known for.

The grading structure developed alongside the industry: Bourbon variety arrived from Brazil in 1893, and by the 1930s a formal auction and classification system had taken shape. Screen size alone does not determine quality, so lots are also assessed on cup character, with the K72 washed process shaping much of the flavor profile buyers look for in kenya coffee.

Kenyan coffee is famous for its clean and refreshing taste and bright fruit acidity, and is a classic region in the hearts of many coffee lovers. Starting from the Kiambu region where Thika is located, this article systematically reviews the growing conditions, historical development, distribution of ten major regions, and official grading system of Kenyan coffee, and deeply analyzes how K72 washed processing shapes its signature flavor. The article also uses Front Street Coffee Kenya Little Tomato as an example to share specific pour-over parameters and brewing steps, helping readers fully understand the coffee charm of this East African producing country.

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Many friends who have just been introduced to specialty coffee, after first realizing that coffee can actually have acidity, often ask: "Which coffee is the most acidic?" Faced with this question, Front Street's baristas almost invariably think of Kenya. Kenyan coffee drinks clean and translucent, with a full and solid mouthfeel and lively, bright fruit acidity. Almost everyone who has tasted it is deeply attracted by it.

Coffee Growing Conditions

Kenya is located in East Africa, with the equator passing through its center and the East African Rift Valley running north to south. The country is mainly composed of plateaus, with an average altitude of about 1,500 meters. Mount Kirinyaga, the second-highest peak in Africa (also known as Mount Kenya), reaches 5,199 meters, and its summit is covered with snow all year round.

Kenya belongs to a tropical producing region, with two rainy seasons each year, corresponding to harvest periods from October to December and June to August. Coffee cultivation is mainly concentrated in volcanic areas at altitudes of 1,600 to 2,100 meters. Due to the higher altitude, the ripening cycle of coffee cherries is extended, allowing the beans to fully accumulate aromatic substances, ultimately presenting obvious fruit acidity and hard bean density.

Coffee Growing History

Although neighboring Ethiopia is recognized as the birthplace of coffee, Kenya's coffee-growing history did not begin until the end of the 19th century. In 1893, missionaries brought Bourbon variety from Brazil into Kenya. In 1895, Britain made Kenya a colony, designated it as the "East Africa Protectorate," and took control of all local crops, including coffee.

From 1900 to 1933, the colonial government established the Coffee Board (CB), responsible for licensing, inspection, and promotion of coffee. In 1934, auctions became one of the sales methods for Kenyan coffee, and the first coffee auction was not actually held until September 1935. In 1946, the Coffee Marketing Board (CMB) was established and began full operation on July 1, 1947, but the institution was abolished in 1971.

Introduction to Kenyan Coffee Regions

There are 10 main coffee-producing regions in Kenya: Nyeri, Murang’a, Kirinyaga, Embu, Meru, Kiambu, Machakos, Nakuru, and Kisii.

[Nyeri/Nyeri]

The Nyeri producing region is located in central Kenya and is home to Mount Kenya, an extinct volcano. The fertile volcanic red soil here provides exceptional conditions for producing Kenya's highest-quality coffee. The region is dominated by cooperatives made up of smallholders, while large estates are relatively rare. The growing altitude ranges from 1,200 to 2,300 meters.

[Murang’a]

The Murang’a producing region belongs to Central Province and has about 100,000 coffee farmers. This was one of the first places where missionaries chose to settle. It also has fertile volcanic soil, and the number of smallholders far exceeds that of estates. The growing altitude ranges from 1,350 to 1,940 meters.

[Kirinyaga]

The Kirinyaga producing region is located east of the Nyeri producing region, and its volcanic soil is also fertile. The area is mostly dominated by coffee produced by smallholders, and washing stations also produce many exceptionally high-quality lots. The growing altitude ranges from 1,300 to 1,900 meters.

[Embu]

The Embu producing region is close to Mount Kenya, and its name comes from Embu town. About 70% of the local population is engaged in small-scale farming, and almost all coffee beans come from smallholders, with overall production relatively low. The growing altitude ranges from 1,300 to 1,900 meters.

[Meru]

Most coffee in the Meru producing region is grown by smallholders in the foothills of Mount Kenya and the Nyambene Hills. The name Meru comes from the local Meru people. In the 1930s, they became the earliest local Kenyan ethnic group to produce coffee, thanks to the Devonshire White Paper signed in 1923, which safeguarded the rights of Kenyan Africans. The growing altitude ranges from 1,300 to 1,950 meters.

[Kiambu]

The Kiambu producing region is located in central Kenya and is dominated by large coffee estates. However, with the advancement of urbanization, the number of estates has continued to decrease. Coffee from Kiambu is usually sold under sub-region names, such as Thika, Ruiru, and Limuru. In addition, there are also many smallholders in this producing region. The growing altitude ranges from 1,500 to 2,200 meters.

[Machakos]

Machakos is a relatively small county in central Kenya, named after Machako town. Coffee production in this producing region is composed of both estates and smallholders. The growing altitude ranges from 1,400 to 1,850 meters.

[Nakuru]

The Nakuru producing region is located in central Kenya and has the highest coffee-growing altitude among the central producing regions. However, some high-altitude plants stop growing due to dieback. The name of the producing region comes from Nakuru town. The growing altitude ranges from 1,850 to 2,200 meters.

[Kisii]

The Kisii producing region is located in the southwest of Kenya's coffee-producing areas, close to Lake Victoria, and is relatively small. Most coffee in the area comes from cooperatives formed by free small-scale producers. The growing altitude ranges from 1,450 to 1,800 meters.

Kenya Coffee Grading System

Friends who have followed Front Street's Kenyan coffee content must be familiar with the name Kenya AA. Kenya developed its coffee economy during the colonial period, and the entire industry system leaned toward refined management. In terms of selection and breeding, grading, and processing methods, Kenya was ahead of many coffee-producing countries at the time. It was not until decades later, when other countries gradually recognized the value of refined management and began to imitate it, that Kenya's unique position gradually changed.

1. Classified by size, shape, and weight

E: elephant bean, above screen 18 (including round beans), including large round beans. Like PB, the quantity is relatively small.

AA: screen 17-18. Front Street Little Tomato coffee beans belong to the highest AA grade.

AB: screen 15-16, a mixture of Grade A and Grade B. Above screen 17 (6.8 mm) is Grade A, and above screen 16 (6.3 mm) is Grade B.

TT: light beans screened out from AA and AB by an airflow separator.

PB: above screen 15, round bean, peaberry, accounting for about 10% of Kenyan coffee.

C: screen 12-14, as well as light beans screened out from PB by an airflow separator.

T: below screen 12, with more defective beans, broken beans, and light beans.

HE: grades outside the above are classified as HE (Hulled Ears).

2. Raw beans that have not undergone official standard grading are UG (ungrade)

E, AA, AB, PB→UG1

C, TT, T, HE→UG2

3. MBUNI (natural beans, non-washed processing)

All raw beans undergo gravity separator

MH: heavy mbuni, heavy beans, yellow, no black beans, fragments, dried fruit, or other defects, with typical natural flavor in the cup and no flavor defects.

ML: light mbuni, yellow-green, with a small number of insect-damaged beans or black beans, no stinker beans or fragments, and no earthy or other bad flavors in the cup.

The above is Kenya's official national grading system. In addition, Kenyan exporters or green coffee traders also add special grading for AA and AB green coffee beans (not officially recognized by the Kenyan state), in order: TOP, PLUS (+), FAQ.

Reasons for the Taste Characteristics of Kenyan Coffee

The fermentation time of beans from Central and South America in washing tanks usually does not exceed 36 hours, while Kenya's washing time is as long as 72 hours. After 30 to 48 hours of fermentation, the parchment beans are removed from the tank. At this point, the mucilage on the bean surface has been completely removed, but they still need to be soaked in clean water for 24 hours. After cupping many beans, Front Street believes that this additional fermentation process should be closely related to the bright and clean flavor characteristics of Kenya AA coffee.

How to Drink Kenyan Coffee

Taking Front Street Coffee Kenya Little Tomato as an example:

Front Street Coffee: Kenya · Little Tomato Coffee Beans

Producing region: Asali Washing Station, Thika producing region, Kenya

Altitude: 1,550 m—1,750 m

Variety: SL28, SL34

Processing method: K72 washed processing

Flavor description: smoked plum, cherry tomato, snow pear, yellow sugar, plum

Front Street Coffee Pour-Over Parameters Sharing

Dripper: Hario V60

Dose: 15 g

Coffee-to-water ratio: 1:15

Water temperature: 90°C

Grind size: EK43s#10 (80% passing through No. 20 standard sieve)

In the first stage, pour 30 g of water and bloom for 30 seconds. In the second stage, pour water to 125 g in stages. When the water level drops to the point where the coffee bed is about to be exposed, proceed with the third stage of pouring until 225 g, then stop. After the water in the dripper has completely dripped into the server, remove the dripper. The total extraction time is about 2 minutes 00 seconds.

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