A complete guide to roasting Kenyan coffee beans

Kahwei Yoong
-
June 4, 2021
roasting kenyan coffee

There are few better places in the world for growing coffee than Kenya. Home to rich volcanic soil, high altitudes, and favourable weather conditions, the country has long been recognised for the quality and complexity of its coffee beans.

In total, Kenya grows five distinct varieties, all of which offer their own unique set of characteristics, from bright acidity and berry tones, to full body and wine-like flavour notes. However, like all coffees, the final outcome of Kenyan beans hinges significantly on the ability of the roaster to unlock their full potential.

To find out more about roasting Kenyan coffee, I spoke with 2018 Finland Cup Tasters Champion and Head of Production at The Gentlemen Baristas, Roosa Jalonen.

Read next: A Pocket-Sized Guide To Roasting Ethiopian Coffee

kenyan coffee beans

Overview of Kenyan coffee

In Kenya, coffee is cultivated across more than 115,000 hectares in 32 regions. Production is dominated by small-scale farmers who produce around 70% of the country’s total output, while a robust cooperative system ensures fair prices and sustainable working conditions. 

Almost all of the coffee produced in Kenya is arabica grown on fertile volcanic soil at 1,400 to 2,200 metres above sea level. As a result, it qualifies for Strictly High Grown (SHG) or Strictly Hard Bean (SHB) status, which means its beans have more time to develop and absorb nutrients.

Roosa Jalonen is Head of Production at The Gentlemen Baristas in London and a certified arabica Q grader. She tells me that what distinguishes Kenyan coffee for her is its powerful berry flavour notes.

“Traditionally, Kenyan coffee has high acidity and is very juicy,” she says. “Blackcurrants, or currants in general, are very often the dominant flavour notes. In many cases, they taste like Ribena juice.”

Unlike neighbouring Ethiopia, most of the country’s coffee undergoes washed processing. This tends to produce the clean, balanced, and “bright” cup for which Kenyan beans are famous. However, Roosa explains that in recent years, more and more natural-processed coffees have started to appear on the market.

“I was surprised at how intense and beautiful natural Kenyan coffees were,” she says. “As a green coffee buyer and someone who works at a roastery, I think that they could be a new trend in the future.”

roasted coffee beans

Finding the optimum roast profile

When roasting Kenyan coffee, one important aspect that all roasters should understand and consider is its grading system, where green beans are sorted and graded by their sizes (or screen size) post-harvest.

Some common grades include E (elephant beans, largest in size), PB (peaberry), AA (one of the more common grades and generally higher priced), and AB (mix of A grade with 6.8mm screen and B grade with 6.2mm screen). Roosa tells me that AA, AB, and PB are some of the most common grades used in specialty roasteries.

Roosa explains that because of the influence this unique classification system has on a roast, she always makes it her starting point to find out which category the beans fall into.

“My starting point when roasting Kenyan coffee is to understand the grade of the coffee, as well as its density because this can affect the roasting process,” she tells me. “Usually, I apply quite a lot of heat at the beginning of the roast in order to kickstart the development process because Kenyan beans are often dense coffee.” 

Indeed, in The Coffee Roaster’s Companion, author Scott Rao suggests that denser and larger beans would require more heat energy to penetrate its core, and therefore charging the beans at a higher temperature is an appropriate measure.

When deciding on a roasting profile, it is also helpful to have a clear idea of the characteristics you want to highlight. Roosa says that in her roastery, the team will conduct a number of test roasts to gain an understanding of the beans that will help them determine what they want.

For example, when Roosa tested a sample roast that had strong passion fruit flavours, she made sure to create a roast profile that would let the passion fruit notes shine through the coffee.

“On a personal note, I think that Kenyan coffee works better as filter coffee,” she says. “I believe that you get more out of the coffee if it is roasted on the lighter roast spectrum rather than aimed towards high end temperature and high development time ratio.”

At the same time however, it also depends on what flavours the coffee has to give. Roosa recalls a recent project where she adjusted the roast profile for a Kenya AB Kagumoini from filter roast to omni-roast because the beans were slightly past their peak. An omni-roast is one in which the coffee is suitable for both espresso and filter.

roasting kenyan coffee

What to avoid when roasting Kenyan coffee beans

To achieve better roast results with Kenyan coffee, Roosa shares a few pointers that demand close attention.

“The main thing to avoid when roasting Kenyan coffee is the rate of rise (RoR) crash after first crack,” she says.

During first crack, the beans begin to undergo an exothermic reaction, in which built-up energy, water vapour, and carbon dioxide (CO2) are released from their core. Consequently, the bean surface temperature decreases briefly from the cooling effect of evaporation which, in turn, causes the RoR to plummet.

To manage this in the case of Kenyan coffee, Roosa’s advice is to take a step back and look at the roast development as a whole, rather than focusing solely on one area.

“Sometimes, roasters get too fixated on the development time ratio and neglect other aspects of the roast,” she explains. “I think specifically for Kenyan coffee, it is so important to look at the beginning and the middle of the roast, making sure that the beans are getting enough development during those times.

“After the first crack, if your roast does not have enough momentum left or if it just crashes, there is nothing much that you can do to control the roast afterwards.”

Furthermore, because of the RoR crash after first crack, you can also end up with a flick, which indicates an acceleration in the bean rate of rise.

“This is also something to try to avoid because it does not add to the development of beans, but rather, you are just baking the coffee,” Roosa says.

sustainable coffee packaging

At MTPak Coffee, we offer a range of sustainable packaging options that will maintain the freshness and preserve all the unique characteristics of your Kenyan coffee. 

Our high quality coffee bags can be fully customised to highlight the distinct flavour notes and story of your coffee. They can also be fitted with recyclable degassing valves and resealable zippers, adding extra convenience for consumers. 

For more information on our sustainable coffee packaging, contact our team here

MTPak Coffee

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A complete guide to roasting Kenyan coffee beans
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