Kenya SL28 34 Pour-over Temperature? Kenya Coffee Varieties K7 Batian Ruiru Characteristics and Historical Stories

FrontStreet Coffee has recommended the Asalia coffee beans from Kenya to everyone more than once, and I believe everyone is already very familiar with the brewing details of this coffee bean.

Dripper: V60 dripper

Water Temperature: 90-92°C

Dose: 15 grams

Coffee-to-Water Ratio: 1:15

Grind Size: Medium-fine grind (80% retention rate on China standard #20 sieve)

Brewing Method: Multi-stage extraction

Bloom with 30 grams of water for about 30 seconds. When injecting 125 grams of water with a small stream in the center in stages, wait until the water level drops to the point where the coffee bed is about to be exposed, then continue injecting water to 225 grams to finish. When the water level drops to the point where the coffee bed is about to be exposed, remove the dripper (timing starts from the beginning of blooming). Extraction time is 2'00".

Coffee Varieties

Kenya's red-orange, fertile volcanic soil, the region's mild climate, ideal equatorial sunlight, and carefully selected Kenyan coffee plant varieties all contribute to exceptional coffee quality.

Nowadays, the mainstream Kenyan coffee consists of the following five varieties:

• SL 28
• SL 34
• K7
• Ruiru 11
• Batian

First, it's important to understand that the SL28 and SL34 varieties were developed and researched by Scott Agricultural Laboratory between 1922-1944, followed by the development of the K7 variety. In the late 1960s, Kenya experienced a very serious outbreak of coffee berry disease and leaf rust. The CRF Coffee Research Foundation took over the government-managed laboratory at that time and quickly developed resistant coffee varieties—Ruiru 11 and Batian.

Commercial coffee varieties produced by the Kenya Coffee Research Foundation include: Ruiri 11, which grows well at all altitudes and has resistance to coffee berry disease and coffee leaf rust; SL34, which grows well in high-altitude areas with abundant rainfall; SL28, which grows well in medium to high altitude areas where coffee leaf rust is not severe; and Kent, which grows well in low altitude areas that are also susceptible to coffee leaf rust.

The African variety K7 is a mission variety of the French Bourbon dynasty (Coffea arabica var. bourbon) grown on the Legetet estate in Muhroni, Kenya. It was selected for cultivation based on cupping trials. Robusta coffee (Coffea canephora var. robusta) grows in the humid low-altitude areas of western Kenya.

SL28 Coffee Variety

SL28 is the flagship of Kenyan coffee varieties. Due to SL28's exceptional cup quality and high yield, buyers flock to it. Scott Agricultural Laboratory selected SL28 in 1931 from a drought-resistant variety from Tanganyika—this variety can be traced back to the Bourbon variety. The SL prefix is an acronym for Scott Agricultural Laboratory, and 28 is the serial number.

Botanical and Characteristics of SL28

SL28 is tolerant to water stress because it originates from drought-resistant varieties from Tanganyika. It can still bear fruit for a long period without water. This is because SL28 has deep roots. You can even leave SL28 trees unattended for years and then restore them to full production. This is a very unique quality.

SL28 is a tall variety with green but occasionally bronze-colored shoot tips. The beans are large, the yield is high, and the tree bears fruit after two years. SL28 thrives in medium to high altitudes of 1500 to 1700 masl or higher. Agronomists recommend planting 1330 trees per hectare to ensure high quality.

But besides high cup quality, SL28 also has some disadvantages. The SL28 variety is susceptible (sensitive) to all major coffee diseases: Coffee Berry Disease (CBD), Coffee Leaf Rust (CLR), and Coffee Bacterial Blight (CBB). These diseases continuously threaten Kenya's most popular variety.

SL34 Coffee Variety

The SL34 variety is very similar to SL28. The cup quality is outstanding, and the yield is high. However, buyers consider SL34's quality to be slightly inferior to SL28.

Scott Agricultural Laboratory developed SL34 from the "French Mission" (Bourbon) variety through single tree selection. But as mentioned earlier, recent investigations tell us that SL34 originates from a Typica-like variety.

Botanical and Characteristics of SL34

In the field, you can recognize SL34 by its tall stature and deep bronze, sometimes even green, shoot tips. Like SL28, SL34 is water stress tolerant and deep-rooted. However, the berries and beans are larger and heavier than SL28. SL34 takes two years to flower and bear fruit.

The SL34 variety has adapted to high-altitude areas, +1500 masl, with abundant rainfall. But this is where the danger lies. Because SL34 thrives in dense areas, farmers need strict protocols to control coffee berry disease. Besides being susceptible to CBD, CLR and CBB are also threats.

K7 Coffee Variety

The K7 coffee variety is the third successful variety developed by Scott Agricultural Laboratory. It has high yield and good quality. You can trace K7 back to the Bourbon variety. Like its predecessors SL28 and SL34, K7 is drought-resistant. But K7 has a feature that other Scott Laboratories varieties lack.

Botanical and Characteristics of K7

K7 is the only traditional variety in Kenya that can resist certain races of CLR and CBD. This is why K7 is an ideal choice for low-growing areas, from 1200 to 1500 masl, where CLR exists. After planting K7, you can expect to harvest cherries after two years.

K7 is tall and has widespread lateral lines. The leaves are bronze-colored with light bronze shoots. Compared to the rich acidity of SL28 and SL34 varieties, K7 has more subtle cup characteristics. The acidity is mild and subtle, but the body is full.

Ruiru 11 Coffee Variety

In the late 1960s, when coffee berry disease and leaf rust were rampant, the Ruiru Coffee Research Foundation's mission was to develop disease-resistant varieties. In 1985, they successfully cultivated Ruiru 11. Ruiru 11 is a composite variety of 66 hybrid siblings. That is to say, Ruiru 11 has characteristics from 66 lines.

Botanical and Characteristics of Ruiru 11

The Coffee Research Foundation named it Ruiru 11 for two reasons. First, the variety was developed at the Ruiru Coffee Research Station, hence the Ruiru prefix. The code "11" indicates that it was the first variety developed by Kenyans, released from a single-direction hybrid; in other words, it's an F1 hybrid. Ruiru 11 can resist CBD and CLR and is suitable for all growing altitudes in Kenya.

It doesn't produce cherries after two years, but after 1.5 years. Another feature that farmers like is the compact growth. This means Ruiru 11 plants don't need much space to produce good yields. They can plant 2500 trees per hectare instead of 1330 trees per hectare for SL28 and SL34. Farmers can expand their production with Ruiru 11 trees.

Besides volume output, Ruiru 11 also has several disadvantages. Unless grafted onto traditional varieties, the variety is sensitive to water stress. And the quality is slightly inferior to SL28, SL34, and K7 varieties.

Batian Coffee Variety

The Coffee Research Foundation released another disease-resistant variety in 2010: Batian. Batian can resist CBD and CLR. But what makes Batian special is its morphological characteristics similar to SL28. In the field, you might mistake Batian for SL28. And in the cup, Batian matches the quality of SL varieties.

Botanical and Characteristics of Batian

Batian is an interesting variety because it combines the best of both worlds:

• It has resistance to CBD and CLR.
• It gives farmers high yields; plant density is 1900 trees per hectare.
• The cherries mature earlier than traditional varieties.
• The bean size is larger than other Kenyan varieties.
• And it has high quality; it can even compete with SL28 and SL34.

Most importantly, Batian goes into production after 1.5 years. Batian is a tall variety with bronze-colored leaves, and the cherries and beans are large, just like SL34. If we delve deep into the variety's pedigree, we find that Batian is a combination of beautiful varieties. Batian has traces of SL34, SL28, K7, SL4, Rume Sudan, N39, and even Timor hybrids.

Batian has the potential to become Kenya's most popular variety, but it is very sensitive to acidic soils.

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