Arabica
SL17
Also known as: Scott Laboratories 17
SL17 is one of the SL ( Scott Laboratories ) varieties selected in Kenya . While less famous than SL28 and SL34 , SL17 is part of the important group of Kenya n selections that contribute to the country's coffee heritage.
Key Takeaways
- SL17 is one of the SL (Scott Laboratories) varieties selected in Kenya.
- SL17 is less well-documented and less widely planted than SL28 and SL34.
SL17 is one of the SL ( Scott Laboratories ) varieties selected in Kenya . While less famous than SL28 and SL34 , SL17 is part of the important group of Kenya n selections that contribute to the country's coffee heritage.
SL17 is one of the SL (Scott Laboratories) varieties selected in Kenya. While less famous than SL28 and SL34, SL17 is part of the important group of Kenyan selections that contribute to the country's coffee heritage.
Origin
Selected by Scott Laboratories in Kenya.
History
SL17 was selected by Scott Laboratories in Kenya as part of the same selection program that produced SL28, SL34, and other SL varieties in the 1930s-1940s. The SL program selected individual trees from various populations for desirable characteristics. SL17 is less well-documented and less widely planted than SL28 and SL34 but is part of the important group of Kenyan selections.
Discovery
Selected by Scott Laboratories in Kenya in the 1930s-1940s.
Genetics and Lineage
SL17 is an Arabica selection from Kenyan populations. Its exact genetic group is less well-documented than SL28 or SL34.
Parent Varieties
Hybrid Status: Not a hybrid. SL17 is a selection from a single tree population.
Growth Characteristics
SL17 is a tall tree, typical of Kenyan selections.
Tree Size: Tall (3 to 4 meters at maturity)
Yield: Moderate.
Disease Resistance: Moderate. Susceptible to coffee leaf rust.
Climate and Growing Conditions
Thrives in Kenyan highland conditions at elevations of 1,400 to 1,900 meters.
Climate Preferences: Tropical highland climate.
Rainfall: 1,200 to 1,800mm annually.
Elevation Range: 1,400-1,900 meters
Processing Compatibility
Compatible with all processing methods. Washed processing is traditional in Kenya.
Roasting Behavior
SL17 beans are dense and take heat well.
Cup Profile
SL17 produces a good-quality cup with bright acidity and notes of citrus and berry, similar to but generally less complex than SL28.
Professional Cupping Notes
SL17 lots typically score 83 to 86 points in SCA cupping.
Common Defects
- •Susceptible to coffee leaf rust
- •Less prized than SL28 or SL34
Brewing Recommendations
Works well as pour over and filtered coffee.
Countries Where Grown
Notable Farms
Interesting Facts
- •SL17 is one of the SL (Scott Laboratories) varieties selected in Kenya.
- •SL17 is less well-documented and less widely planted than SL28 and SL34.
Frequently Asked Questions
Sources
- •World Coffee Research
- •Kenya Coffee Board
Related Varieties
Batian
Batian was developed to combine disease resistance with the cup quality of SL28. Well-grown Batian produces a bright, juicy cup with notes of blackcurrant,...
ArabicaRuiru 11
Ruiru 11's cup quality is debated. Well-grown Ruiru 11 can produce a bright, fruity cup reminiscent of SL28 but generally with less complexity and intensity....
ArabicaSL14
SL14 produces a good-quality cup with bright acidity, medium body, and notes of citrus, berry, and chocolate. The cup is similar to other Kenyan SL varieties...
ArabicaSL28
SL28 is renowned for its intensely fruity, juicy, and complex cup profile. It has bright, wine-like acidity, a juicy body, and distinctive notes of blackcurrant, blackberry, tomato, and sometimes citrus. The cup is bold, complex, and unmistakably Kenyan.
ArabicaSL34
SL34 has a rich, complex cup with a heavier body and darker fruit notes than SL28. It has bright acidity, a full, syrupy body, and notes of blackcurrant, plum, dark cherry, and chocolate. The cup is complex, rich, and less overtly fruity than SL28.
Related Encyclopedia Entries
Acidity
In coffee tasting, acidity refers to the bright, vibrant, and often fruity quality that gives coffee its liveliness and structure. Unlike the negative connotation of acidity in everyday language, coffee acidity is a desirable characteristic when balanced. It is perceived as a pleasant tartness or brightness on the palate, similar to the acidity in wine or fruit.
Origins & GeographyCoffea Arabica: The Specialty Coffee Species Explained
Arabica coffee (Coffea arabica) is a species of coffee plant native to the highland forests of Ethiopia and South Sudan. It is the most widely cultivated coffee species worldwide, accounting for approximately 60 to 70 percent of global coffee production. Arabica is prized for its complex flavor, refined acidity, and aromatic diversity, producing notes ranging from floral and citrus to chocolate and caramel depending on origin, variety, and processing.
Coffee ScienceCoffee Leaf Rust
Hemileia vastatrix belongs to the order Pucciniales and is an obligate biotrophic fungus, meaning it requires living host tissue to survive. The infection cycle begins when urediniospores are deposited on the abaxial (underside) surface of the coffee leaf, typically via wind or rain splash. Germination occurs only in the presence of free water—such as dew or rainfall—within a temperature range of 15°C to 28°C. Upon germination, the fungus enters the leaf through the stomata and establishes a mycelium that colonizes the internal tissue. The visual manifestation of the disease begins as small, chlorotic spots that expand into characteristic orange, powdery pustules. These pustules contain thousands of spores capable of further infection. The physiological impact includes a rapid reduction in photosynthetic capacity and the eventual abscission of the leaf. Severe cases lead to 'dieback,' where the plant's branches wither due to carbohydrate depletion, often resulting in the death of the tree or a total loss of the following year's crop.
Coffee ScienceExtraction
Extraction is the process of dissolving soluble compounds from ground coffee into water, producing the beverage we know as coffee. During extraction, water pulls acids, sugars, lipids, carbohydrates, and melanoidins from the coffee grounds in a sequence that shapes flavor, body, and aroma.
EspressoGroup Head
<h2>Technical Specifications and Maintenance</h2><p>Commercial group heads are engineered to withstand continuous operation at pressures up to 12 bars, though the industry standard remains 9 bars. The internal seal is maintained by a group gasket, which requires replacement every 3 to 6 months in commercial environments as the elastomer hardens due to repeated thermal cycling. The assembly also houses a dispersion screw that secures the shower screen; in some designs, this screw incorporates a secondary dispersion block to further diffuse water flow. Periodic backflushing with chemical detergents like sodium percarbonate is required to remove polymerized coffee oils that accumulate behind the screen and inside the solenoid valve, which can otherwise impart rancid flavors to the espresso. Advanced machines may feature independent P.I.D. (Proportional-Integral-Derivative) controllers specifically for the group head to allow baristas to fine-tune the temperature for specific roast profiles, such as increasing heat to 96°C for light-roasted heirloom varietals to maximize solubility.</p>
Related Book Chapters
- •Chapter 4: Varietals & Cultivars
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Keith E. Lyons
Author, Researcher & Coffee Educator
Keith E. Lyons is the author of The Complete World of Coffee and the publisher behind Lyons Den Publishing. A licensed trauma therapist turned specialty coffee writer, Keith blends scientific rigor with genuine passion for the craft of coffee.
Last Reviewed
July 22, 2026
Sources & References
(2)Claims are cited to verifiable sources. Peer-reviewed research is marked.
- 1World Coffee Research
- 2Kenya Coffee Board
Authoritative References
Editorial Standards
- • Fact-checked against peer-reviewed coffee science research and industry standards.
- • Reviewed by the author with documented sources for every factual claim.
- • Updated regularly; the "Last Reviewed" date reflects the most recent verification.
- • Corrections are made promptly when new research or evidence emerges.
Our editorial process prioritizes accuracy, scientific rigor, and practical relevance for coffee enthusiasts and professionals alike.
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lyonsdenpublishers@gmail.comIntelligent Recommendations
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SL14
SL14 produces a good-quality cup with bright acidity, medium body, and notes of citrus, berry, and chocolate. The cup is similar to other Kenyan SL varieties...
SL34
SL34 has a rich, complex cup with a heavier body and darker fruit notes than SL28. It has bright acidity, a full, syrupy body, and notes of blackcurrant, plum, dark cherry, and chocolate. The cup is complex, rich, and less overtly fruity than SL28.
SL28
SL28 is renowned for its intensely fruity, juicy, and complex cup profile. It has bright, wine-like acidity, a juicy body, and distinctive notes of blackcurrant, blackberry, tomato, and sometimes citrus. The cup is bold, complex, and unmistakably Kenyan.
Batian
Batian was developed to combine disease resistance with the cup quality of SL28. Well-grown Batian produces a bright, juicy cup with notes of blackcurrant,...
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Reference definitions that complement this page.
Sl34 Coffee Variety
SL34 is a Kenyan selection from Kabete, often confused with SL28 but descended from a different Bourbon lineage. It thrives at slightly lower altitudes and produces a fuller-bodied cup than SL28, with the same signature Kenyan blackcurrant acidity but a heavier, more syrupy mouthfeel.
Sl28 Coffee Variety
SL28 is the legendary Kenyan arabica selection from Ruiru, bred by Scott Laboratories for drought resistance and cup quality. It produces the archetypal Kenyan cup: explosive blackcurrant, citrus brightness, and a wine-like complexity that makes it the benchmark for specialty coffee worldwide.
Batian Coffee Variety
Batian is a modern Kenyan release from the Coffee Research Institute, bred for disease resistance while preserving the cup quality of SL28 and SL34. Named after Mount Kenya's peak, it delivers bright acidity and blackcurrant notes at altitudes above 1,700 meters.
French Mission Coffee Variety
French Mission is one of the original coffee varieties planted in Kenya, introduced by French missionaries in the late 1800s. It laid the genetic foundation for Kenya's renowned SL varieties and still produces bright, blackcurrant-toned cups at high altitudes.