Kenya Coffee Green Bean Processing Methods Flavor Description Taste Profile Grind Settings Origin Varieties Introduction

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Many people's impression of Kenyan coffee beans still停留在 having an obvious small tomato flavor, believing that Kenyan coffee without small tomato flavor is not authentic. FrontStreet Coffee believes that we cannot define Kenyan regional coffee beans this way. The original flavor characteristic of the Kenyan region is a rich juice-like texture with substantial mouthfeel.

For all plants, soil and environment affect plant growth, and coffee trees are no exception. Changes in the region's climate, soil, and other factors lead to flavor variations in coffee beans from each harvest season. In recent months, FrontStreet Coffee has cupped many varieties of Kenyan coffee beans and found that regardless of which Kenyan region they come from, they all possess a rich, juicy mouthfeel. Of course, they are not identical—there are still differences in acidity and flavor.

Kenya: A Premier Coffee Producing Nation

Kenya is a renowned coffee-producing country in East Africa and one of the world's important origins for specialty coffee. Kenyan coffee is characterized by its full-bodied flavor and distinctive profile. The coffee trade system also features a sophisticated grading system. Bean size classifications such as AA or AB do not necessarily equate to flavor quality—the Coffee Board's auction batches are determined by cupping quality, and premium Kenyan auction prices remain high. Most Kenyan coffee grows at altitudes between 1,500-2,100 meters, with two harvests annually. To ensure only ripe berries are picked, people must patrol the forests approximately seven times.

Kenya has two coffee sales systems: auctions at the Nairobi Coffee Exchange (central auction system), where 85% of coffee beans are traded through the auction system, or through direct trade (commonly known as the "second window"), where only 15% of coffee beans are traded through this direct trade model.

The Nairobi Coffee Exchange

The Nairobi Coffee Exchange (NCE) is where Kenyan coffee is traded through this auction system. Auctions are currently held biweekly, every Tuesday. Before the bidding begins, market agents deliver green bean samples to the NCE twelve days in advance for display, giving buyers sufficient time to select suitable items for cupping. Each auction features hundreds of coffee varieties, sometimes exceeding a thousand. The entire process takes nearly a full day, starting at 9:30 AM and continuing until 4-5 PM without interruption. Dozens of buyers in the venue immerse themselves in the green bean catalog, bidding and competing while continuously recording the transaction prices of each green bean.

The current Kenyan coffee industry chain roughly follows this pattern: Coffee farmers harvest coffee fruits and send them to washing stations for preliminary density grading, then hand them to market agents. At the washing stations, coffee beans are already graded by screen size into the familiar AA, AB, PB, C categories, then green bean samples are transferred to the NCE to participate in auctions and provide product catalogs. At the auction, buyers bid on green beans that meet their requirements, and finally export them abroad. From the above, the NCE belongs to the middle segment of the entire industry chain, providing an auction platform.

Kenyan Coffee Bean Grades

AA Plus (AA+): AA-grade beans with particularly excellent cup quality (flavor, mouthfeel).

AA: Screen Size 17-18.

AB: Screen Size 15-16, representing the majority of production.

C: Screen Size smaller than AB.

TT: Lighter-weight beans sifted from AA and AB grade beans using air classifiers.

T: Lighter-weight beans sifted from C grade beans using air classifiers.

E Elephant Bean: Large mutant beans where two beans merge, also called Elephant ear beans.

PB Peaberry: Classified by shape, unrelated to flavor or weight.

Kenyan Coffee Growing Regions

Kenya's coffee production is concentrated in six main regions: Thika, Kirinyaga, Mt. Kenya West, Nyeri, Kiambu, and Muranga. The harvest periods for these six major regions are October-December (main season) and June-August (secondary season). Among these, Nyeri and Kirinyaga are the most famous.

Nyeri, located in the high mountainous area near Mount Kenya, is an important Kenyan specialty coffee region with an average altitude exceeding 1,500 meters. Many of Kenya's finest coffees are produced in this area. Nyeri has sufficient altitude and is situated east of the Aberdare Mountains, also forming the isthmus between Mount Kenya and the mountain itself. Due to its high terrain and fertile soil, Nyeri has become a central hub for Kenyan coffee, with well-developed coffee-related industry facilities.

The Kirinyaga region is situated on the slopes of Mount Kenya at altitudes of 1,300-1,900 meters. Adjacent to the Nyeri region, it is world-renowned for coffee with intense flavors, rich layers, and substantial mouthfeel. Together with Nyeri, it is recognized as one of Kenya's two most excellent coffee-producing regions.

Coffee Varieties

SL28 was selected in 1935 as a single variety from drought-resistant populations in Tanganyika. The SL28 variety is suitable for medium to high altitude regions and has drought resistance capabilities but is sensitive to major coffee diseases. SL28 beans resemble the Bourbon variety—round and substantial. Recent genetic testing has confirmed that SL28 belongs to the Bourbon genetic group.

SL34 was initially selected in the late 1930s at Kenya's Scott Agricultural Laboratories. SL34 was selected from a tree on the Kabete Loreshu estate in Kenya, which was called "French Mission." SL34 beans resemble the Typica variety. FrontStreet Coffee screens Kenyan beans for those with Typica-like appearance—elongated, oval-shaped, and flatter when viewed from the side. Recent genetic testing indicates that SL34 is related to the Typica genome.

Coffee Processing Methods

Generally, the washed processing method for coffee beans involves first removing the peel and pulp of coffee cherries, leaving only a thin layer of mucosa for water washing and fermentation for 24-48 hours, followed by drying with machines or sun-drying. However, Kenyan washed processing differs, with the entire fermentation process reaching 72 hours.

Kenyan washed processing uses a cyclic method of post-fermentation washing. The highest quality cherries are selected on the harvest day for pulping and fermentation, with a fermentation time of 24 hours. After 24 hours, they are washed with clean river water. Then, they undergo another 24-hour fermentation with clean river water, followed by washing, repeating this cycle three times to achieve 72 hours. This is why it's called the Kenyan 72-hour fermented washed processing method, abbreviated as K72. FrontStreet Coffee believes that this processing method allows coffee beans to ferment for extended periods at low temperatures, resulting in brighter, cleaner, yet fuller flavors!

Next, FrontStreet Coffee compares coffee beans from two regions through roasting, cupping, and brewing to see how their flavors differ.

FrontStreet Coffee - Kenya Gachatha AA Coffee Beans

Region: Kenya Nyeri Gachatha Cooperative

Processing Station: Gathaithi Processing Station

Altitude: 1825m

Varieties: SL28 & SL34

Processing Method: K72 Washed

FrontStreet Coffee - Kenya Mugaya AA Coffee Beans

Region: Kenya Mugaya Processing Station

Altitude: 1400m

Varieties: SL28 & SL34

Processing Method: K72 Washed

Harvest Season: 2020

FrontStreet Coffee Roasting Records

Gachatha Coffee Bean Roasting: FrontStreet Coffee's roaster used a Yangjia 800N semi-direct heat roaster with a 480g batch size. The drum temperature was set to 165°C when beans were loaded, with the air damper at 3 and heat at 120. Return temperature: 1'28". When temperature reached 140°C, the air damper was adjusted to 4. At 6'00", temperature reached 153°C, the bean surface turned yellow, and grassy aroma completely disappeared, indicating dehydration completion. When ugly wrinkles and black spots appeared on the bean surface, and the toast aroma clearly transformed to coffee aroma, this can be defined as the prelude to first crack. At this point, one must listen carefully for the sound of first crack. First crack began at 9'17", with the air damper unchanged, heat reduced from 188 to 90. First crack development time was 2'00", with discharge at 193.5°C.

Mugaya Coffee Bean Roasting: FrontStreet Coffee's roaster used a Yangjia 800N semi-direct heat roaster with a 480g batch size. The drum temperature was set to 160°C when beans were loaded, with the air damper at 3 and heat at 120. Return temperature: 1'28". When temperature reached 130°C, the air damper was adjusted to 4. At 6'00", temperature reached 154.6°C, the bean surface turned yellow, and grassy aroma completely disappeared, indicating dehydration completion. When ugly wrinkles and black spots appeared on the bean surface, and the toast aroma clearly transformed to coffee aroma, this can be defined as the prelude to first crack. At this point, one must listen carefully for the sound of first crack. First crack began at 9'28", with the air damper unchanged. First crack development time was 2'20", with discharge at 193.8°C.

FrontStreet Coffee Cupping Report

FrontStreet Coffee conducts cupping 8-24 hours after roasting sample coffee beans. FrontStreet Coffee's baristas typically use 200ml ceramic bowls for cupping. The water temperature used for cupping is 94°C. Grind size is controlled to achieve 70%-75% pass-through through a #20 standard sieve (0.85mm). Ratio: 11g of coffee powder to 200ml of hot water, i.e., 1:18.18, which extracts a concentration within the golden cup range of 1.15%-1.35%, with an infusion time of 4 minutes.

Gachatha Coffee Beans: Dry aroma: Citrus; Wet aroma: Plum; Flavor: Citrus, plum, berries, honey, grapes, tea-like notes.

Mugaya Coffee Beans: Dry aroma: Berries; Wet aroma: Caramel; Flavor: Dark plum, plum, grapes, caramel, nuts.

From cupping these two beans, we can notice that the higher-altitude Gachatha coffee beans have richer acidity. This is because the greater altitude results in larger day-night temperature differences, slowing coffee tree growth and allowing more time for flavor development.

FrontStreet Coffee Brewing Tips

Dripper: V60 #01

Water Temperature: 90°C

Coffee Dose: 15g

Coffee-to-Water Ratio: 1:16

Grind Size: Medium-fine (77% pass-through through #20 sieve)

FrontStreet Coffee Brewing Method: First wet the filter paper and preheat the dripper and coffee pot. Use 30g of water for a 30-second bloom, then pour with a small circular flow to 130g before pausing. When the water level drops and is about to expose the coffee bed, continue pouring to 240g and stop. When the water level drops and is about to expose the coffee bed again, remove the dripper. (Timing starts from the bloom) Total extraction time is 2 minutes.

Important Notice :

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