Both cultivars trace their roots to Scott Laboratories in Kenya, but they diverge sharply in altitude needs, cup character, and disease resistance. For Uganda's growing conditions, the choice between them shapes everything from yield to export pricing.
Uganda's Arabica sector relies heavily on two Scott Laboratories selections: SL14 and SL28. Both arrived in East Africa during the mid-20th century as part of a systematic effort to improve disease resistance and cup quality across the region. Today they anchor the portfolios of washing stations from Mount Elgon to the Rwenzoris. Buyers evaluating Ugandan Arabica lots will encounter both names regularly, and understanding the differences is essential to making sourcing decisions that match your roast profile and customer expectations.
The shorthand: SL14 is the drought-tolerant workhorse for mid-altitude zones, while SL28 is the high-altitude specialist that, when grown in the right conditions, produces some of the most distinctive coffees Uganda can offer. This comparison explores the origins, agronomic profiles, cup characteristics, and market positioning of both cultivars across Uganda's coffee landscape.
The table below captures the key distinctions that matter for buying decisions. Note that actual cup scores and yields vary by farm management, processing method, and seasonal conditions.
| Attribute | SL14 | SL28 |
|---|---|---|
| Origin | Scott Labs, Kenya (1930s); drought-tolerant selection | Scott Labs, Kenya (1931); selected from Tanganyika DR |
| Optimal altitude (Uganda) | 1,200 - 1,700 m | 1,600 - 2,100 m |
| Rainfall requirement | 900 - 1,200 mm/year | 1,200+ mm/year |
| Disease resistance | Good tolerance to coffee leaf rust and CBD | Susceptible to CBD and leaf rust; requires careful management |
| Yield potential | High; 1,500 - 2,200 kg/ha clean coffee | Moderate; 800 - 1,400 kg/ha clean coffee |
| Screen size (typical) | Screen 15 - 17; medium to bold bean | Screen 16 - 18; large, elongated bean |
| Cup score range (SCA) | 80 - 84; sometimes higher with careful processing | 83 - 88; regularly reaches specialty threshold |
| Primary Uganda regions | Mt. Elgon mid-slopes, West Nile, mid-Rwenzori | Upper Mt. Elgon, high Rwenzori, Kisoro highlands |
| Cup character | Brown sugar, citrus, moderate body, clean finish | Blackcurrant, red berries, winey acidity, complex |
| Market positioning | Solid premium Arabica; blends and single-origin | Specialty single-origin; microlot potential |
SL14 is the practical choice for much of Uganda's mid-altitude coffee land. It was selected for drought tolerance and consistent yield, traits that serve farmers well in areas like the lower slopes of Mount Elgon and the West Nile region, where rainfall can be less predictable. Estates and cooperatives value SL14 for its forgiving agronomy: it establishes readily, responds well to pruning, and produces dependable volumes year after year.
In the cup, SL14 tends toward brown sugar sweetness with citrus notes, typically lemon or orange. The body is moderate and the acidity is balanced rather than sharp. Washed SL14 from well-managed washing stations on Mount Elgon can score 82 to 84 points, making it a reliable choice for premium blends and mid-tier single-origin offerings. Its screen size, usually 15 to 17, makes it suitable for most roast profiles.
For buyers building volume programs, SL14 offers consistency. Multiple regions produce it in commercial quantities, including Bugisu, Sebei, and West Nile. It blends well with other East African Arabicas and holds up in medium to dark roasts. Visit our Uganda coffee regions guide to explore where SL14 is grown.
SL28 demands more from its environment but rewards the effort with a cup profile that can rival East Africa's finest. In Uganda, it thrives above 1,600 metres on the upper slopes of Mount Elgon, the high Rwenzori range, and the volcanic terrain around Kisoro. At these altitudes, cooler nights slow cherry maturation, concentrating sugars and developing the complex acidity that defines the variety.
The cup is unmistakable: blackcurrant and red berry notes, often with a wine-like acidity and a syrupy body. Well-processed Ugandan SL28 lots have scored 86 to 88 points in competition, and a small number of microlots have pushed past 89. The bean is large and elongated, typically screening at 16 to 18, which roasts evenly and presents beautifully in packaging. The trade-off is lower yield and higher disease pressure. CBD (Coffee Berry Disease) is a particular concern, and farmers growing SL28 need disciplined fungicide programs.
SL28 is not ubiquitous in Uganda, but it is growing. Specialty-focused exporters and cooperatives are expanding plantings in high-altitude zones. Buyers who identify reliable SL28 sources early can secure consistent access to a variety with strong market recognition and premium pricing potential. Check our buyer's guide for tips on sourcing specialty Ugandan Arabica.
The choice between SL14 and SL28 depends on your market position and roast philosophy. If you need a versatile, good-quality Arabica at competitive pricing for blends or everyday single-origin bags, SL14 delivers. If your customers seek distinctive origin character and are willing to pay a premium, SL28 from Uganda's high-altitude zones offers a compelling narrative and a memorable cup.
Many Ugandan exporters now offer separated lots by cultivar, and some washing stations operate with cultivar-specific day lots. When cupping Ugandan samples, ask your supplier to identify the cultivar alongside the region and processing method. A cupping table with both SL14 and SL28 from the same washing station reveals dramatically how much genetics matter alongside terroir. For a broader look at Uganda's coffee types, see our varieties overview.
Our buyer's guide covers pricing, logistics, and finding the right exporter for your volume and quality requirements.
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