How Does Roast Level Change Kenya Coffee Flavor?

Kenyan coffee is known for bright acidity, but dark roasting was once a mainstream practice there. Two Kenyan AA lots, Karogoto and Asaliya, show the split clearly: light roasts keep the berry and citrus acidity, while dark roasts bring cedar, herbs, almond, hazelnut, and chocolate, with softer acidity and a fuller body.

Both lots are Kenyan-style washed, grown at 1,550 to 1,800 meters, and planted with SL28 and SL34. Those Bourbon variants have dense, hard beans, so heat penetrates slowly and a longer roast helps full development; the beans were roasted to the start of second crack. Pour-over, French press, and espresso each handle the two roast levels differently in the cup.

Kenyan coffee has always been known for its bright acidity, but historically there was also a mainstream practice of dark roasting. This article uses the two Kenyan AA beans selected by Front Street Coffee—Karogoto and Asaliya—to compare the flavor and mouthfeel differences between dark roast and light roast, and records in detail the brewing performance of pour-over, French press, and a dark-roasted Kenyan blend espresso. The article also starts from the roasting technology background of the second wave of coffee, explaining the origin of the claim that Kenyan coffee should be dark roasted, as well as the changing logic of roast level selection in the specialty coffee era, providing coffee lovers with a reference that balances theory and practice.

Most people who love Kenyan coffee are attracted by that bright acidity. However, while looking through some materials, Front Street discovered that in the past Kenya actually also had a dark roast practice, which is very different from today's common understanding of Kenyan flavor. So what exactly does Kenyan coffee taste like after dark roasting? Let's take a look together.

The two beans used this time are Kenyan AA Karogoto and Asaliya, with producing areas distributed in Nyeri and Kiambu Thika in Kenya. In terms of altitude, Karogoto is 1,800 meters, and Asaliya is between 1,550 and 1,750 meters, both belonging to relatively high-altitude lots. The processing method is the same Kenyan-style washed method, and the varieties are SL28 and SL34.

Both beans have relatively thick flesh, and combined with the characteristics of high-altitude hard beans, as well as the relatively hard bean quality of the Bourbon variants SL28 and SL34, overall the heat permeability of Kenyan washed beans is not ideal. It takes a longer time for heat to reach the core of the bean and fully develop, so it is indeed relatively suitable for a dark roast approach.

We separately gave both coffees a dark roast treatment, roasting until the start of second crack and the wrinkles on the bean surface had completely unfolded before dropping, then conducted cupping.

Flavor evaluation

Karogoto: cedar, flowers, herbs, almond, with berry acidity and a balanced mouthfeel.

Asaliya: citrus, berries, hazelnut, chocolate, with soft acidity, a full body, and a highly sweet finish.

Compared with the light roast versions, the acidity of both dark-roasted Kenyans dropped noticeably. The tomato note in Karogoto's original dry aroma basically disappeared, replaced by a rich spice aroma; Asaliya's blackcurrant-like acidic aroma was also gone, developing aromas of berries and citrus.

Brewing evaluation

We selected Asaliya, which had the better flavor performance, and conducted brewing tests with two different devices.

1. Pour-over

V60 dripper, 16 grams of coffee, medium-coarse grind, brewing water temperature 88°C, coffee-to-water ratio 1:16, brewing time 2 minutes 15 seconds.

Method: first pour 30g water and bloom for 30 seconds, second pour 130g, pause pouring briefly, third pour 100g.

The wet aroma presents floral and citrus notes. On entry there is a slight astringency, accompanied by almond and berry flavors. The body is full, with cedar and toffee tones. The finish is warm citrus.

2. French press

2-person French press, 16 grams of coffee, medium-coarse grind, brewing water temperature 87°C, coffee-to-water ratio 1:16, brewing time 2 minutes 30 seconds.

Method: preheat the pot first, then add the coffee grounds, pour in 30 grams of water and stir slightly, bloom for 30 seconds; for the second pour, add 230 grams of water, cover and steep for 2 minutes, then press down quickly.

The Kenyan coffee made with the French press has a thin layer of oil floating on the surface, a cleaner mouthfeel, and the astringency disappears, presenting citrus, almond, and caramel flavors. In the later stage and finish there is a rich berry aroma, with cedar notes faintly appearing in the base, and a very long finish.

We found that this dark-roasted Asaliya was unexpectedly suitable for the French press, so we further thought: what would happen if it were made into espresso? Kenyan coffee as SOE has very high acidity, a relatively thin body, and an unsatisfactory mouthfeel. The editors, who are not acid lovers, decided to add a bean with high body and mouthfeel to pair with it, and thus a rather unusual combination was born.

Dark-roasted Mandheling + dark-roasted Kenya 1:1 espresso

This blend espresso actually turned out very good! Rich crema, full body, with the strong aroma of toffee, chocolate, and peach, and a lasting almond flavor. Made into milk coffee, it is very rich and smooth, reminding one of a heavy dark chocolate cranberry brownie cake.

After research, if Kenyan coffee beans are used as single-origin coffee, although dark roasting brings woody aromatic qualities from dry distillation reactions and heavy caramelized flavors, it also erases its original high-quality floral and fruity flavors, especially the berry notes and juicy feel, so it can be said to be a double-edged sword. But when Kenyan beans are used for blending, in order to obtain a full and balanced mouthfeel, dark roasting is a relatively suitable roast level.

Finally, let's talk about why there is the saying that Kenyan coffee should be dark roasted. The emergence of this view was mainly during the second wave of coffee, that is, the era when espresso was dominant. In addition, the roasting machines and roasting technology at the time were still relatively backward, and processing methods were also relatively rough. Roasters' understanding of coffee beans also led them to classify some hard washed beans as difficult to roast (indeed, Kenyan coffee is not easy to roast through), and using dark roasting could effectively solve the problem of underdeveloped beans.

Coffee bean roasting—a bunch of physicochemical formulas + a little imagination = infinite possibilities

With the rise of specialty coffee, European-style light roasting highlights enzymatic floral and fruity aromas. More and more beans that were originally thought to be suitable only for dark roasting have moved toward medium or even light roasting, in order to express their most original regional flavor. Our exploration of the degree to which a bean should be roasted has thus gained broader room for imagination.

The above content is compiled by CoffeeHunters, a coffee news website.