SL34 Coffee: A Kenyan Cultivar With Incredible Potential

The unglamorously named SL34 is one of the best coffees in the world – if you can grow it.

Kenya has gained a well-desered reputation for one of the world’s best coffee growing regions in recent decades, known for bold brews with a unique winey acidity. Much of this success stems from the past efforts of Scott Labs, which lends its initials to today’s topic: SL34 coffee.

While perhaps not quite as famous as its cousin, SL28, SL34 is every bit as exciting in the cup. Here’s everything you need to know about this important variety.

What Is SL34 Coffee?

SL34 coffee is a coffee cultivar most commonly grown in Kenya. It was developed in the 1930s by Scott Agricultural Laborotories, which named all its selections from that time period with the initials SL (for Scott Labs).

Historical documents suggest that SL34 is an Arabica species derived from a French Mission coffee tree on the Kenyan Loresho Estate in Kabete, which collaborated with Scott Labs on research. However, more recent genetic testing indicates the presence of Typica coffee beans as a genetic parent (1).

SL34 coffee plants are tall with dark bronze-tipped leaves and relatively large beans. When grown successfully at high altitudes, they can yield exceptionally high cup quality – often winning specialty coffee awards. Unfortunately, they are highly susceptible to coffee leaf rust, coffee berry disease, and nematodes, making planting SL34 crops risky for farmers.

Interestingly, setting aside their pest and disease vulnerability, SL34 coffee trees are surprisingly low-maintenance. Even with years of neglect, they will continue to produce coffee, albeit with lower returns. And this decrease in yield is easily correctable once you resume proper care (2).

What Does SL34 Coffee Taste Like?

SL34 is most celebrated for its vibrant acidity, which tends to be more citrusy and less winey than other Kenyan beans. Expect punchy notes of lemon, orange, and sour blackberry. 

It’s a complex and medium-bodied coffee, with lots of fruits and florals to balance the acidity. The best SL34 beans I’ve brewed are lighter roasts and feature flavors of ripe berries, stone fruit, jasmine, and honey. Medium roasts are still very juicy but have more notes of caramel and occasionally creamy nuts like cashew or hazelnut. It’s rare to find a dark roast SL34.

How Should You Brew SL34 Coffee Beans?

Brewing methods are largely a matter of personal taste, so I won’t offer strict guidance here. 

My preference is to brew these specialty beans using a paper-filter infusion method to showcase their complexity and subtle flavors. I’d recommend a Hario V60 or Fellow Stagg. If you enjoy a fuller-bodied coffee, consider replacing the paper filter with a very fine metal filter, like the Able Kone.

Final Thoughts

SL34 coffee is a Kenyan cultivar known in equal parts for its exceptional cup quality and terrible disease resistance. It’s a very challenging coffee for farmers to grow, but as a result, those producing it tend to do so with the utmost care. If you can get your hands on a bag of single-origin SL34 beans, you’re in for a real treat!