Kenya Single-Origin Coffee Flavor Profile & Characteristics Kenya Coffee Bean Size Grading System

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Many people's impression of Kenyan coffee beans still停留在着明显的小番茄味道，认为没有小番茄味道的就不是肯尼亚咖啡。FrontStreet Coffee believes we cannot define a Kenyan coffee bean this way. The original flavor characteristic of Kenyan regions is a full-bodied juice texture.

For all plants, soil and environment affect their growth, and coffee trees are no exception. Changes in the region's climate and soil will lead to flavor variations in coffee beans from each harvest season. FrontStreet Coffee has cupped many varieties of coffee beans from Kenya over the past few months and found that regardless of which Kenyan region they come from, they all have a rich juice texture. Of course, they're not exactly the same—there are still differences in acidity and flavor.

Kenya: A Premium Coffee Origin

Kenya is a renowned coffee-producing country in East Africa and an important origin for global specialty coffee. Kenyan coffee is full-flavored with distinctive characteristics, and its coffee trade system follows a sophisticated process. Coffee bean size grading such as AA or AB doesn't necessarily equate to flavor quality. The Coffee Board's auction batches are determined based on cupping quality, and premium Kenyan auction prices remain high. Most Kenyan coffee grows at altitudes between 1500-2100 meters, with harvests twice a year. To ensure only ripe berries are picked, people must patrol the fields approximately 7 times.

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

Nairobi Coffee Exchange and Coffee Supply Chain

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

The current Kenyan coffee supply chain generally follows this process: Coffee farmers harvest coffee cherries and send them to washing stations, where preliminary density sorting is conducted. The beans are then handed over to market agents. At the washing stations, coffee beans are sorted by screen size into the well-known AA, AB, PB, C grades. 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 description, the NCE belongs to the midstream of the entire supply 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 mesh.

AB: Screen Size 15-16 mesh, accounting for the majority of production.

C: Screen Size smaller than AB.

TT: Lighter-weight beans blown out from AA and AB grade beans using airflow screeners.

T: Lighter-weight beans blown out from C grade beans using airflow screeners.

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

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

Kenyan Coffee Growing Regions

The six main growing regions include: Thika, Kirinyaga, Mt. Kenya West, Nyeri, Kiambu, and Muranga. The harvest periods for all six major regions are October-December (main season) and June-August (secondary season) each year. Among these, Nyeri and Kirinyaga are the most famous.

Nyeri is located in the highlands near Mount Kenya and is an important Kenyan premium-grade growing region, with an average altitude exceeding 1500 meters. Many excellent Kenyan coffees are produced in this area. Nyeri has sufficient altitude and is situated east of the Aberdare Mountains, forming a peninsula between Mount Kenya and Ben Mountain. 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 growing region is situated on the slopes of Mount Kenya, at altitudes of 1300-1900 meters. Adjacent to the Nyeri region, it's world-renowned for coffee with intense flavors, rich layers, and solid mouthfeel. Together with the Nyeri region, it's recognized as the two best growing regions in Kenya today.

Coffee Bean Varieties

SL28 was selected in 1935 as a single variety from drought-resistant strains in Tanganyika. The SL28 variety is suitable for medium to high altitude areas and has drought resistance capabilities but is sensitive to major coffee diseases. SL28 beans resemble the Bourbon variety - round and full-bodied. Recent genetic testing has confirmed that the SL28 variety 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 Loresho estate in Kenya, which was called "French Mission." SL34 beans resemble the Typica variety. FrontStreet Coffee screens beans from Kenyan coffee to find those that resemble Typica beans - elongated, oval-shaped, and flatter when viewed from the side. Recent genetic testing indicates that SL34 is related to the Typica genome.

Coffee Bean Processing Methods

Generally, the washed processing method for coffee beans involves first removing the skin and pulp of coffee cherries, leaving only a thin layer of mucosa for washing and fermentation for 24-48 hours, followed by machine or sun drying. However, the Kenyan washed processing method is quite different—the entire fermentation process reaches 72 hours.

The Kenyan washed processing method uses a repeated cycle of fermentation and washing. On the day of harvest, the highest quality cherries are selected for depulping 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 again. This cycle is repeated 3 times to reach 72 hours, hence the name "Kenyan 72-Hour Fermentation Washed Processing Method," abbreviated as K72. FrontStreet Coffee believes this processing method allows coffee beans to ferment for a long time at low temperatures, giving the beans brighter, cleaner, yet fuller flavors!

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

FrontStreet Coffee's Kenyan Coffee Selections

FrontStreet Coffee — Kenya Gathaithi Cooperative AB Coffee Beans

Region: Kenya Nyeri Gathaithi Cooperative

Processing Station: Gathaithi Processing Station

Altitude: 1825m

Variety: SL28 & SL34

Processing Method: K72 Washed

FrontStreet Coffee — Kenya Mugaya AB Coffee Beans

Region: Kenya Mugaya Processing Station

Altitude: 1400m

Variety: SL28 & SL34

Processing Method: K72 Washed

Season: 2020

FrontStreet Coffee Roasting Records

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

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

FrontStreet Coffee Cupping Report

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

Gathaithi 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 Gathaithi coffee beans have richer acidity. The greater day-night temperature difference caused by high altitude slows coffee tree growth, allowing more time for coffee flavor development.

FrontStreet Coffee Brewing Tips

Dripper: V60 #01

Water Temperature: 90°C

Dose: 15g

Coffee-to-Water Ratio: 1:16

Grind Size: Medium-fine (77% retention on #20 sieve)

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

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473