How Does the Kenya Coffee Grading System Work?

Kenya's coffee grading system sorts beans first by size and shape under rules tied to the 1934 auction mechanism, giving grades such as AA, AB, PB, C, E, TT, T, and MH/ML. A separate quality rating from the Kenya Coffee Research Institute adds labels like TOP, Plus, and FAQ, so AA or TOP on a bag describes different things.

AA means the largest screen size, not automatically the highest cup quality, which is why the country also scores lots across green beans, roasted beans, and cupping. Smallholders pool their harvest through cooperatives and send it to the central auction in Nairobi, where the same standards apply for domestic sale and export, helping link quality to price.

When purchasing Kenyan coffee, what exactly do the words "AA" and "TOP" commonly seen on the packaging represent? This article systematically sorts out Kenya's coffee grading system, from the bean-size grading under the 1934 auction system (AA, AB, PB, C, E, TT, T, MH/ML) to the secondary quality rating established by the Kenya Coffee Research Institute (TOP, Plus, FAQ), and analyzes the comprehensive scoring mechanism across three dimensions: green beans, roasted beans, and cupping. It also presents the producing-region information and brewing parameters for Front Street Coffee's Kenya Small Tomato coffee beans, helping you understand the practical meaning behind the grading labels.

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Kenyan coffee has always been renowned for its richly layered berry-like acidity, sugarcane-like sweetness, and bright, juicy acidity, earning a large following worldwide. However, many people notice when selecting Kenyan beans that the packaging often bears a prefix like "AA," such as FrontStreet Coffee's currently available Kenya Asalia AA TOP. So what exactly do the "AA" and "TOP" that follow represent?

Let's start with "AA," which indicates the grade of this batch of coffee beans. Coffee is essentially an agricultural product, and quality inevitably varies, so each producing country customizes grading rules suited to its own circumstances. This is done to form homogeneous commercial lots from coffees that meet established quality standards, thereby promoting a fairer and more transparent pricing system.

The Kenyan government established an auction mechanism as early as 1934, with the aim of directly linking coffee quality to price. Every year, a large number of Kenyan smallholder farmers pool their beans through coffee cooperatives and send them uniformly to the central auction house in the capital, Nairobi. Before the formal auction, these coffees must go through a rigorous grading process.

Whether for domestic sale or export, the same set of grading standards is used. The rating is based on bean size, shape, color, and density, usually with bean size and overall quality as the core indicators, and with clear regulations, divided in order into the grades AA, AB, PB, C, E, TT, and T. Strict grading helps ensure the overall quality of the coffee beans.

AA-grade coffee beans have a screen size between 17 and 18 mesh and perform excellently in density. They are locally recognized as the highest quality, with quite elegant taste and flavor.

AB-grade coffee beans are between 16 and 17 mesh. Although their quality is not as good as AA, they are more affordable and also quite popular in the market. They also have the largest output, with about 40% of Kenyan coffee belonging to the AB grade.

PB refers to round green beans, meaning that only one round bean develops inside the coffee fruit rather than the usual two flat beans. Only 5% of Kenyan coffee contains such round beans. It is merely a classification by appearance and has no relation to flavor or weight.

C-grade coffee beans are between 12 and 14 mesh and are relatively small. This grade is basically not included in the category of specialty coffee.

E-grade coffee beans are called Elephant in full, commonly known as elephant beans. They share similarities with round beans and are a special type of abnormally developed bean. This kind of bean forms when two coffee beans intertwine during growth, ultimately producing one exceptionally large coffee bean, with a mesh size above 21, and they are extremely rare.

TT-grade coffee beans are light beans selected by air separators from E, AA, and AB beans, usually between 16 and 20 mesh.

T-grade coffee beans are broken beans, defective beans, and excessively small beans separated from C-grade beans, generally below 12 mesh.

The MH/ML grade refers to coffee beans of relatively low quality, mostly processed by natural drying, and only sold domestically, not exported.

From this we can see that in Kenya's grading system, "AA" represents the highest local grade. However, bean size cannot directly determine whether coffee flavor is good or bad; the growing environment is the key factor affecting the flavor direction during the coffee bean's growth. For this reason, local coffee research institutions, together with green bean traders' associations, separately established another grading method to conduct a secondary rating of coffees intended for export.

This system is called the Kenyan Classification Procedure by Quality Assessment, established by the Kenya Coffee Research Institute. "TOP," "Plus (+)," and "FAQ" are labels used in the secondary rating, usually following the original grade, and are mainly divided according to cupping scores.

The TOP level corresponds to a cupping score above 86, Plus (+) to between 84 and 86, and FAQ to around 83 to 84. However, this system has not received official Kenyan certification, so most Kenyan beans currently seen on the market are still mainly classified by conventional size grading.

The following is Kenya's current new coffee grading standard:

According to FrontStreet Coffee's understanding, when assessing coffee quality, the Kenya Coffee Research Institute and the local industry are accustomed to adopting a coffee bean quality grading procedure formulated by that research institute, conducting comprehensive grading from three dimensions: green bean quality, roasted bean quality, and cupping quality.

Green bean quality: subdivided into green bean apparent size, green bean color, and defects. Roasted bean quality: subdivided into the state of the center cut, roasted bean condition, and defective beans. Cupping quality: scored by acidity, body/texture, flavor, and negative defects.

Combining the scores from the three aspects, coffee beans are classified into grades 1 to 10, with grade 1 being the best and grade 10 the worst.

From the above, it can be seen that the difference between AA-grade, AB-grade, and PB-grade coffee beans lies only in bean size, but overall, coffee beans with larger mesh sizes have a relatively lower defect rate, and their flavor is naturally cleaner, so their price is correspondingly higher.

FrontStreet Kenya Small Tomato Coffee Beans

Country: Kenya Region: Asali (Honey Processing Station) Altitude: 1550-1750m Variety: SL28, SL34 Processing method: 72-hour washed processing Flavor: snow pear, smoked plum, yellow sugar, cherry tomato, plum

FrontStreet Brewing Recommendations

FrontStreet Coffee, considering that this bean uses a medium-light roast, will choose a higher water temperature and a faster-flow dripper. The main purpose is to extract its bright acidity with high temperature, while at the same time not wanting high temperature to cause over-extraction, so a faster-flow V60 dripper was chosen.

Coffee-to-water ratio: 1:15

Coffee powder: 15g

Total water poured: 225ml

Water temperature: 91℃

Grind size: fine granulated sugar coarseness | EK43s setting 10 (80% passing rate through a No. 20 standard sieve)

Pour 30 grams of water in the first stage for a 30-second bloom, then pour 95 grams (the electronic scale shows about 125 grams), completing the pour in about 1 minute. When the water level drops to 2/3 of the coffee bed, pour the remaining 100 grams (the electronic scale shows about 225 grams), completing the pour in about 1 minute 40 seconds. Dripping is completed at 2'00", remove the dripper, and extraction is complete.

Brewed flavor: On the palate there are flavors of smoked plum and cherry tomato; the acidity is intense and full-bodied, with prominent sweetness in the middle and a juicy feel; the finish has berry aroma and yellow sugar sweetness, along with green tea aroma.

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