Kenya SL28 SL34 Coffee Bean Variety Characteristics Description | Kenya AA AB Grade Coffee Bean Flavor

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FrontStreet Coffee's Kenyan coffee beans occupy the African specialty coffee market with their extremely pleasant acidity. However, the cultivation history of Kenyan coffee is not particularly long compared to other producing regions, yet it has consistently maintained stable coffee bean quality. FrontStreet Coffee believes this is attributed to Kenya's unique coffee varieties SL28 and SL34. In this article, FrontStreet Coffee will introduce the unique coffee bean varieties of Kenya.

What are the characteristics of FrontStreet Coffee's Kenya SL28 coffee variety?

The emergence of SL28 variety coffee beans was due to the Kenyan government's great emphasis on coffee cultivation. Therefore, in the 1930s, the Kenyan government established a laboratory specifically responsible for selecting coffee varieties for future cultivation in Kenya. At that time, the ancient Typica variety had poor resistance to diseases and pests and was difficult to cultivate. Kenya's coffee cultivation history was not long, meaning coffee variety selection was crucial. After selecting good varieties, they could be promoted globally for coffee farmers, saving them from pest disasters.

This laboratory is now the renowned "Scott Laboratory" in Kenya. Between 1935-1939, it selected forty-two different individual coffee trees, studying their yield, quality, and resistance to drought and diseases, naming them with the laboratory's English initials "SL".

According to FrontStreet Coffee, SL28 was first selected and cultivated from a drought-resistant tree variety from Tanganyika in 1935. According to historical records, in 1931, Scott Laboratory's coffee cultivator AD Trench discovered a variety that seemed tolerant to drought and diseases during an inspection of Tanganyika (now Tanzania) in the Moduli area. He collected seeds and brought them back to Scott Laboratory. After its drought resistance was verified, it was widely cultivated until it was replaced by its descendant SL28.

And to this day, SL28 remains one of Africa's most famous and respected varieties. It has spread from its selection location in Kenya in the 1930s to other parts of Africa (especially Arabica growing areas in Uganda), and now to Latin America. The SL28 variety is suitable for medium to high altitude areas, has drought resistance capabilities, but is sensitive to major coffee diseases. SL28 can be found in many parts of Kenya, and even with 60-80 years of age, it remains highly productive.

FrontStreet Coffee understands that recent genetic testing has also confirmed that the SL28 variety belongs to the Bourbon genetic group. Therefore, SL28 variety coffee beans resemble Bourbon varieties in appearance, being round and thick. (As shown in the picture)

What are the characteristics of Kenya SL34 coffee variety?

SL34 was first selected from the "French Mission" (Bourbon variety) at the Kabete Loresho estate. However, according to FrontStreet Coffee's research, current genetic testing of this variety has confirmed it has Typica genetic group, and its plant characteristics are also similar to Typica. Therefore, it is believed that SL34 originated from Typica. Because SL34 is close to the Typica variety, these coffee beans are elongated, oval-shaped, and appear flatter from the side. (As shown in the picture)

What are the flavor differences between SL28 and SL34 coffee beans?

After understanding the characteristics of these two coffee bean varieties, FrontStreet Coffee will share the differences between these two coffee beans. According to FrontStreet Coffee, SL-28 has gained higher reputation, while SL-34 has larger harvest yields and is cultivated at slightly lower altitudes. According to SL laboratory botanists, SL28 and SL34 are genetic variants. Among them, SL28 has mixed lineage of Mocha and Yemeni Typica. The original goal of cultivating SL28 was to mass-produce coffee beans that combined high quality with resistance to diseases and pests. Although SL28's later yields were not as massive as expected, because of its copper-colored leaves and fava bean-shaped beans with wonderful sweetness, balance, and complex, variable flavors, as well as significant citrus and dark plum characteristics, it has been preserved to this day.

FrontStreet Coffee believes that SL34 coffee beans have similar flavors to SL28, but besides complex and variable acidity and wonderful sweet finishes, the mouthfeel is heavier, richer, and cleaner than SL28. SL34 has Bourbon and more Typica lineage. Therefore, many of FrontStreet Coffee's current Kenya single-origin coffee beans are mixed varieties of SL28 and SL34.

Additionally, FrontStreet Coffee understands that Kenya subsequently developed Ruiru and Batian varieties of coffee beans. These two varieties are also widely cultivated in Kenya today. Next, FrontStreet Coffee will share the characteristics of these two coffee bean varieties.

Ruiru 11

Ruiru appeared after SL28 and SL34. According to FrontStreet Coffee, in the 1970s, the Ruiru station began trying to cultivate different CBD and rust-resistant varieties. The result was Ruiru 11, released in the 1980s. High yield, with CBD and rust resistance properties, this seemed to be the solution to all of Kenya's coffee production problems.

Batian

The Batian variety was launched by the Coffee Research Institute (CRI) on September 8, 2010, and is the latest variety offered by Kenya. It was a further experiment based on lessons learned from Ruiru 11. Genetically, it is essentially selected from backcrosses of SL28 and SL34, making it closer to SL28 than Ruiru 11. This eliminates problematic Robusta variety coffee bean elements, thereby improving cupping quality.

Kenya Coffee Bean Grading System

Besides coffee varieties, the difference between Kenyan coffee beans and those from other producing regions lies in Kenya's coffee bean grading system. For example, FrontStreet Coffee's store carries FrontStreet Kenya coffee grades such as AA, AB, and PB. Although it's called "grading," does AA grade necessarily taste better than AB grade?

According to FrontStreet Coffee, Kenya's coffee bean grading standard is mainly based on size grading. The difference between AA and AB is only in size. As for taste, FrontStreet Coffee concludes through cupping that both AA and AB grade Kenyan coffee beans are very delicious. Flavor differences between producing regions may mainly come from factors such as region, altitude, and growing conditions. However, AA and AB grade Kenyan coffee are definitely the most quality-guaranteed coffees.

As described above, these grades are only distinctions in bean size. The most famous coffee processing method for FrontStreet Kenya coffee beans is undoubtedly the K72 washed processing method. Therefore, Kenya's highest quality coffee beans are mainly washed. Washed coffee processing is generally divided into eight grades:

E: Elephant Bean, also called Elephant ear, flat beans with particle size above 19 mesh
AA: Particle size 17 to 18 mesh

AB: Particle size 15 to 16 mesh, accounting for the majority of production
TT: Lighter weight beans blown from AA and AB grade beans using air screeners
C: Smaller than AB screen size / below 14 mesh, too small to be classified as specialty grade
T: Lighter weight beans blown from C grade beans (below 14 mesh) using air screeners, meaning both size and density are too small for specialty grade
PB: Peaberry, meaning round beans, classified by shape rather than size, unrelated to flavor or weight, accounting for about 10% of total production
UG: Those that do not meet the above standards

Additionally, there are lower quality natural coffee bean grades that do not undergo Kenyan-style washed processing due to poorer quality and are generally used for the Kenyan domestic market. This bean grade is called M'buni.

MH: M'buni Heavy = large beans
ML: M'buni Light = small beans

In addition, FrontStreet Coffee wants to emphasize that this "green bean grading system" standard still in use today was issued by government agencies in 1938, even 40 years earlier than the birth of the "specialty coffee" concept. Therefore, Kenya now has new coffee bean grading standard concepts, but the size-based grading standard is still more common today.

The following are Kenya's current new coffee grading standards:

According to FrontStreet Coffee, the Kenya Coffee Research Institute and local industry commonly use a "Coffee Bean Quality Grading Procedure" formulated by the Kenya Coffee Research Institute when identifying coffee quality, grading comprehensively based on three aspects: green bean quality, roasted bean quality, and cupping quality.

Green Bean Quality: Subdivided into green bean appearance and size, green bean color, and defects.
Roasted Bean Quality: Subdivided into central crack condition, roasted bean condition, and defective beans.
Cupping Quality: Scored based on acidity, body/texture, flavor, and negative defects.

Combining the scores from these three aspects, coffee beans are divided into grades 1 to 10, with grade 1 being the best and grade 10 being the worst.

The above is the knowledge about FrontStreet Kenya coffee bean varieties and grading compiled by FrontStreet Coffee, hoping to help coffee enthusiasts who want to understand related knowledge. Next, FrontStreet Coffee will share the flavors and brewing data of FrontStreet Kenya coffee beans.

FrontStreet Coffee Kenya Asalia Coffee Beans

Country: Kenya
Region: Asali (Honey Processing Factory)
Altitude: 1550-1750m
Varieties: SL28, SL34
Processing Method: 72-hour washed processing
Flavor: Snow pear, dark plum, brown sugar, cherry tomato, plum

FrontStreet Coffee Kenya Thaini Estate PB Coffee Beans

Country: Kenya
Region: Thaini Estate
Altitude: 1680m
Varieties: SL28, SL24, Ruiru
Processing Method: 72-hour washed processing
Flavor: Cherry tomato, almond, dark plum, honey, grape

FrontStreet Coffee Roasting Parameters Sharing

FrontStreet Kenya Asalia Coffee Beans:

These FrontStreet Kenya Asalia beans are full and round. To fully express their bright and mellow acidity, FrontStreet Coffee uses light roasting.

Yangjia 800N semi-direct fire, 480g bean input: Heat the roaster to 160°C, set damper to 3, heat power to 120. Return temperature point: 1'28". When temperature rises to 130°C, set damper to 4. Roast to 6'00", temperature 154.6°C, bean surface turns yellow, grassy aroma completely disappears, dehydration completed.

When ugly wrinkles and black spots appear on the bean surface, and the toast aroma clearly changes to coffee aroma, this can be defined as the prelude to first crack. At this time, listen carefully for the sound of first crack. At 9'28" first crack begins, damper unchanged, first crack development time 2'20", discharge at 193.8°C.

FrontStreet Kenya Thaini PB Coffee Beans:

These rich FrontStreet Kenya Thaini coffee beans, due to higher altitude, have harder bean texture. Initially use higher temperature rise, yellowing point around 5 minutes, then reduce heat to enter Maillard reaction, and reduce heat again at 166°C to prolong Maillard reaction time. When first crack begins, heat absorption is strong, so it's recommended to maintain heat at this stage to prevent stalling. First crack development takes more time, which helps reduce acidity and develop flavors.

Yangjia 800N roaster (300g batch), heat to 170°C, heat power 100, damper set to 3; return temperature point 1'42", when roaster temperature reaches 140°C, open damper to 3.5, heat power unchanged; when roaster temperature reaches 149°C, bean surface turns yellow, grassy aroma completely disappears, entering dehydration stage; 7'14" dehydration completed, heat power and damper unchanged; at 7'30", wrinkles and black spots appear on bean surface, toast aroma changes to coffee aroma, prelude to first crack, pay attention to listen for first crack sound. At 8'20" first crack begins, open damper to 4, reduce heat power to 50. Post-first crack development time 1'50", when temperature reaches 188°C, reduce heat to 30, flatten temperature rise, discharge at 193.3°C.

FrontStreet Coffee Brewing Suggestions

Dripper: V60 or cake cup
Water Temperature: 90-91°C
Coffee-to-Water Ratio: 1:15
Grind Size: Fine grind (80% pass rate through China standard #20 sieve)

Brewing Method: Segmented extraction. Use 30g of water for 30-second bloom, then pour in a circular motion with small water flow to 124g for segmentation. When water level drops and is about to expose the coffee bed, continue pouring to 228g and stop. When water level drops and is about to expose the coffee bed, remove the dripper. (Timing starts from bloom) Extraction time: 1'55".

FrontStreet Kenya Asalia Coffee Bean Flavor: Wet aroma has ripe tomato and floral notes. Entry shows cherry tomato and dark plum flavors, with bright acidity, clean and rich mouthfeel. Mid-section has prominent sweetness with juicy sensation. Aftertaste has berry aroma and brown sugar sweetness, with green tea fragrance.

FrontStreet Kenya Thaini Coffee Bean Flavor: Smells floral, entry shows cherry tomato, citrus, and nutty acidity. Mid-section has cream aroma and brown sugar sweet aftertaste. Aftertaste has cocoa and oolong tea sensations. Rich flavor layers with prominent floral notes.

For more specialty coffee beans, please add FrontStreet Coffee on private WeChat, WeChat ID: kaixinguoguo0925

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473