Kenyan Coffee Processing: K72 Double Wash Method - Characteristics, Flavor Profile and Story

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FrontStreet Coffee recently provided a systematic introduction to Ethiopia, the African coffee-producing country. Today, we will also systematically introduce Kenya, another African coffee-producing country. Kenya and Ethiopia share a border. Through comparison, FrontStreet Coffee can say that their greatest similarity lies in their flavor concentration on acidity. However, FrontStreet Coffee's Ethiopian coffee has a relatively gentler acidity—a bright citrus and lemon acidity—while FrontStreet Coffee's Kenyan coffee has a more intense acidity, a direct nerve-striking sensation like cherry tomatoes and preserved plums, tending toward richness.

Kenya Coffee Development

From a geographical perspective, Kenya is located next to Ethiopia, the birthplace of coffee. However, Kenya's coffee development did not naturally progress by leveraging this geographical advantage. It wasn't until the 19th century that coffee was introduced to Kenya by the British.

FrontStreet Coffee has summarized the following points about how Kenya gradually established its own coffee development system:

• In 1883, the British brought coffee to Kenya (in the same year, the French brought coffee to Yunnan; starting at the same time but with different development paths).
• In 1922, Kenya established the Scott Agricultural Laboratory (Scott Labs, where SL28 and SL34 got their names) to engage in coffee cultivation research. In the decade following its establishment, they selected SL28 and SL34 from 42 coffee varieties as the most suitable for cultivation in the region, providing a good beginning for the industry's development. Today, these two varieties occupy 90% of Kenya's cultivation area.
• In 1931, the Kenya Growers Cooperative Union and the Kenya National Coffee Committee were established to guide the development of the coffee industry from both civil and national levels.
• In 1937, the Nairobi Coffee Exchange was established, initiating Kenya's coffee auction system, where good coffee commanded good prices, setting the tone for coffee pricing.
• In 1938, the Kenyan government issued a coffee grading system, which we know today as AA, AB, PB—this system began to provide a basis for the quality of Kenyan coffee.

K72 Processing Method

In addition to the points mentioned above by FrontStreet Coffee, FrontStreet Coffee's Kenyan coffee achievements are also attributed to the use of the K72 processing method, which is an extension of the standard washed method, resulting in a noticeable difference in coffee bean quality. Some people enjoy the intense acidity, while others do not. The natural processing method involves directly drying the beans under the sun after harvesting and then separating them, which is a very labor-saving method. However, it inevitably produces some defective beans during the drying process (possibly due to insufficient or excessive drying, requiring constant manual turning of the coffee beans). The main difference in washed processing is that it's not labor-saving—after harvesting, the pulp is directly removed before drying, which means investment in machinery and equipment, but in return, higher quality coffee beans are obtained.

The Kenya 72-hour processing method, also known as K72 processing method. Coffee cherries are harvested when they reach a sweetness level of 21, with the optimal fruits selected for pulping. They are then soaked in a fermentation tank for 24 hours using clean river water. After 24 hours, they are washed clean, then soaked again in clean river water for another 24 hours of fermentation, then washed clean, and fermented again—repeating this process three times for a total fermentation time of 72 hours. Standard washed fermentation typically lasts no more than 36 hours. This repeated washing and fermentation process gives FrontStreet Coffee's Kenyan coffee beans intense acidity and a delicate texture.

The time required for fermentation depends on many factors. The hotter the environment, the faster the fermentation. After a period of fermentation, the washed processing removes most of the mucilage, then places the beans in a clean water pool for secondary fermentation. It's worth noting that during fermentation, the circulating water needs to be replaced every few hours to prevent the coffee beans from developing unpleasant odors.

Kenya Auction System

When FrontStreet Coffee first entered the coffee industry, we engaged in coffee cultivation and have our own coffee plantations. We also participate in various coffee auction activities in producing regions. On one hand, this is how FrontStreet Coffee understands changes in the global coffee industry; on the other hand, FrontStreet Coffee also wants to share this information through text and images to help everyone better understand coffee.

Returning to Kenya's auction system, FrontStreet Coffee understands that most coffee beans are uniformly graded and inspected by the Kenya Coffee Board before being sold at auctions. This open auction system can be traced back to before 1934. The auction method operates through an agency system. Kenya has 50 licensed agents who send sample beans to their respective clients for cupping. Clients can bid on their preferred coffee through agents at the auction. However, this system seems to encourage middlemen agents while eroding farmers' income. Therefore, in 2006, Kenya opened up to allow 32 independent sales agents to directly negotiate with foreign coffee buyers without going through auctions.

However, all of this must meet the Kenya Coffee Board's standards for quality, storage, and bank guarantees. Both systems operate in parallel. After years of development, it has become the most transparent auction distribution system, where better quality coffee can achieve higher prices through cupping, encouraging more cooperatives and farms to join.

There are two main trading models for coffee in Kenya:

• Auction at the Nairobi Coffee Exchange (Central Auction System): 85% of coffee beans are traded through the auction system.
• Or through direct trade (often called the "Second Window"): Only 15% of coffee beans are traded through the direct trade model.

Kenya Coffee Trading Process

Model 1: Nairobi Coffee Exchange Auction

Since the establishment of the auction system in the 1930s, the vast majority of Kenyan coffee has been traded this way. Coffee auctions are held every Tuesday during the harvest season. It evolved from an "open outcry" auction system where each trader bids by pressing an electric trigger. Through this system, due to competition among agents, the prices of high-quality, highly sought-after coffee soar.

Model 2: Direct Trade

After 2006, the Kenyan government allowed farmers to trade directly with foreign buyers (such as roasters or importers). They can discuss and determine a price different from the auction price before or during the harvest. Some exporters also directly purchase coffee from relevant marketing agents or factories, using the previous week's auction prices for specific grades as a reference for negotiation. Direct trade allows farmers producing high-quality coffee to earn more income. When direct trade is not feasible, the coffee returns to the exchange for auction sale.

Kenya Coffee Cultivation Model

Large plantations: Over 3,000 large farms (including 40,000 hectares of coffee), which account for about 25% of Kenya's coffee-growing land. The remaining 75% consists of agricultural cooperatives, totaling 270 cooperatives composed of approximately 700,000 small-scale farmers growing coffee.

In the 1960s, smallholder cooperatives began developing shared processing plants, enabling them to harvest and process coffee like large plantations. To this day, the high-quality output from specialized processing plants has made Kenyan coffee known to the world.

Small farmers typically harvest hundreds of kilograms annually on a small scale. They decide which nearby processing plant (Coffee Factory) to sell their fruit to based on transportation distance and purchase prices. Farmers own very small plots of land, often measured by the total number of trees on a piece of land, which means producers often have more autonomy to strategically pick coffee cherries and can deliver the ripest coffee cherries to local factories (washed processing plants). Factories generally have abundant water resources for fine washed processing, including soaking coffee beans in fresh water for extended periods to consolidate the unique Kenyan flavor profile.

Kenya Coffee Growing Regions

Kenya's coffee growing regions are mainly distributed in the central and western parts of the country. The main coffee regions in the central area include Kiambu, Nyeri, Kirinyaga, Muranga, Embu, Machakos, Ruiri, and Thika. In the western region, there are Kisii and Bungoma on Mt. Elgon.

FrontStreet Coffee periodically updates the coffee growing regions on its bean list, and Kenya is no exception. Last month, FrontStreet Coffee conducted tasting sessions on a batch of new season Kenyan coffee beans from different growing regions through roasting, cupping, and pour-over brewing. We found that each region has its unique characteristics.

• Kiambu and Muranga show relatively bright and full acidity.
• Nyeri has bright citrus and floral aromas. Although slightly inferior to FrontStreet Coffee's Ethiopian Yirgacheffe, it has a full-bodied berry acidity.
• Kirinyaga's acidity also tends toward brightness and richness, with delicate sweetness.
• Embu's acidity is not as full-bodied and strong as the previous regions, with flavors leaning toward balance and persistent aftertaste.
• Machakos also shows outstanding acidity with a delicate mouthfeel and persistent aftertaste, gradually gaining attention from coffee buyers.
• Kisii and Bungoma differ most from other regions in their prominent fruity sweetness, gentle acidity, and nutty flavors.

FrontStreet Coffee's Kenyan Coffee Varieties

In Kenya, common varieties include SL28, SL34, and Ruiru 11.

In the 1930s, the Kenyan government commissioned the newly established Scott Labs to select varieties suitable for the country. After screening 42 initial varieties and numbering them one by one, SL-28 and SL-34 were finally selected. The former originated from Bourbon, while SL-34 originated from Typica—the two are not varieties from the same series.

The original goal in selecting SL28 was to mass-produce coffee beans that combined high quality with disease resistance. In some regions, the selection goal was primarily high yield and disease resistance, without considering disease resistance. Thanks to its Bourbon genetics, although SL28's yield was not as expected later, its copper-colored leaves and broad bean shape offer wonderful sweetness, balance, and complex, varied flavors, as well as significant citrus and preserved plum characteristics.

SL34 has similar flavors to SL28, but with a softer and cleaner mouthfeel than SL28, in addition to its complex, varied acidity and wonderful sweet finish. SL34 has French Mission, Bourbon, and more Typica lineage. The bean appearance is similar to SL28, but it's better adapted to rainforest growth.

Subsequently proven, the former received quite high praise, typically having blackcurrant-like acidity with complex flavor presentations; the latter, although slightly inferior, still has impressive fruity flavors. These two varieties currently account for 90% of Kenya's production, becoming the generally recognized variety representatives of Kenyan coffee. Currently, South America is also actively introducing SL28 as a cultivation variety.

Ruiru 11: In 1985, during the global coffee leaf rust outbreak, Kenya developed this hybrid variety that prioritized yield over quality. However, its flavor quality is far inferior to the previous SL28 and SL34, and it did not gain traction in the specialty coffee industry. Nevertheless, many suppliers, even those importing famous coffee beans, mix this hybrid into blended coffees (Blend) to reduce costs.

In FrontStreet Coffee's bean list, there is a FrontStreet Coffee Kenyan coffee bean from Sasini Estate that includes the Ruiru 11 variety. It has distinct preserved plum and cherry tomato flavors, almond notes in the middle, and honey in the finish, with a juice-like mouthfeel and bright acidity.

Kenya Coffee Grading

Kenyan coffee beans began using a strict grading system in the 1930s, mainly based on the size, shape, and hardness of the coffee beans. From high to low, they are classified as AA or AA+, AB, PB, C, E, TT, T. This can be used as a basis for selection, and coffee flavor is also considered as a reference. Currently, the most common grades in the mass market are AA, AB, and PB.

Coffee Size Grading

AA grade is a level name for green coffee beans, mainly referring to the size of the beans. AA grade indicates larger coffee beans, generally green coffee beans with particles above 17 mesh (17 mesh = sieve mesh diameter 6.75MM). AA size is 17 and 18 mesh, AB is 15 and 16 mesh.

• AA Plus (AA+): Exceptional cup quality (flavor, mouthfeel) AA grade
• AA Particle Size (Screen Size): 17-18 size
• AB Particle Size (Screen Size): 15-16 size, accounting for the majority of production

• C Particle Size (Screen Size): Smaller than AB
• TT: Lighter-weight beans blown out by an air classifier from AA and AB grade beans
• T: Lighter-weight beans blown out by an air classifier from C grade beans
• E Elephant Bean: Large mutant beans where two beans have merged, also known as Elephant ear
• UG: Those not meeting the above standards
• PB Round Bean (Peaberry): Classified by shape, unrelated to flavor or weight

Flavor Grades

In addition to size grading, Kenya also uses a flavor grading system of TOP, PLUS, and FAQ to select delicious coffee as a reference. The indicators are: green beans (size, color, defects), roasted beans, cup quality (acidity, body, flavor characteristics, defects). In practical application, they simplify it to Acidity-Body-Flavor, quickly scoring each bean on a 1-3 point scale for each item. If a bean is marked as 1-1-1, it corresponds to TOP AA.

Due to multiple factors in the actual trading of Kenyan coffee: 1. High prices, 2. Many batches (the three-item scoring system was specifically designed to handle the many batches), 3. Direct trading channels outside the exchange system, 4. Small quantities.

Therefore, FrontStreet Coffee collects samples frequently,每年从不同的渠道要收集40-50种不同的肯尼亚样品让烘焙师烘出来，喝不同花样的肯尼亚酸，最终选择前街认为最能代表肯尼亚的一个到两个上架。

FrontStreet Coffee's Kenya Asalia Coffee Beans

FrontStreet Coffee brews FrontStreet Coffee's Kenya Small Tomato AA TOP coffee to experience the flavor and mouthfeel brought by Kenya's K72 double-washed processing method.

• Region: Thika, Kenya
• Processing Station: Asali Honey Processing Station
• Altitude: 1550-1750 meters
• Grade: AA TOP
• Varieties: SL28, SL34
• Processing Method: K72 Processing Method

Roasting Suggestions

When FrontStreet Coffee roasts this FrontStreet Coffee Kenya Asalia coffee bean, we consider highlighting its bright acidity profile and adopt a light roast.

• Machine: Yangjia 800N, 550g green beans input
• Bean entry temperature: 200°C
• First crack: 5'30", 154.3°C
• Development after first crack: 2'10", removed from roaster at 191.6°C

Cupping Flavors

When FrontStreet Coffee roasts, we use a multi-group comparison mode, using cupping to evaluate which roasting curve best expresses the coffee bean's flavor.

• Dry aroma: Cherry tomato, berries
• Wet aroma: Tea aroma, caramel
• Palate: Snow pear, preserved plum, cherry tomato, brown sugar, plum

Brewing Suggestions

Considering that this FrontStreet Coffee Kenya Asalia uses a light roasting method, FrontStreet Coffee will use higher water temperature and a faster flow rate dripper. This is mainly because we need high temperature to extract its bright acidity profile, but we don't want over-extraction due to high temperature, so we choose the faster flow rate V60 dripper. The main parameters used are: V60 dripper, 1:15 coffee-to-water ratio, 15g coffee weight, 90°C water temperature, grind size (80% passing through #20 standard sieve).

FrontStreet Coffee Brewing Water Temperature Suggestions

The reason FrontStreet Coffee doesn't specify a particular grind setting is that first, everyone uses different grinders, and second, different coffee beans also require different grind settings. This is related to factors such as the coffee bean's variety, altitude, processing method, roast, etc. Therefore, when FrontStreet Coffee gets a new roasted bean, we first sieve it to determine the appropriate pour-over grind. For this FrontStreet Coffee Kenya Asalia coffee bean, FrontStreet Coffee determined the grind setting to be BG#5D after sieving. However, FrontStreet Coffee recommends that even with the same brand of grinder, it's more rigorous to run it through a sieve.

In terms of brewing technique, FrontStreet Coffee uses segmented extraction, which is the three-stage pouring method. Pour 30g of water for blooming for 30 seconds, then pour 125g in a circular motion for the second stage. When the water level drops to just about to expose the coffee bed, continue pouring to 225g. Total time is 2 minutes (including blooming).

FrontStreet Coffee V60 Pour-over Coffee Blooming

FrontStreet Coffee V60 Pour-over Coffee Second Stage Pouring

FrontStreet Coffee V60 Pour-over Coffee Third Stage Pouring

FrontStreet Coffee's Kenya Asalia Pour-over Flavors

On the palate, there are flavors of preserved plum and cherry tomato, with a mouthfeel of intense, full acidity. The middle section has prominent sweetness with a juice-like sensation, and the aftertaste has berry aroma and brown sugar sweetness, along with green tea fragrance.

For more specialty coffee beans, please add FrontStreet Coffee on private WeChat, WeChat ID: kaixinguoguo0925

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