When people talk about the most acidic coffee, everyone thinks of Kenya. After all, Kenyan coffee is famous for its clean, crisp mouthfeel and its solid, bright, juice-like acidity. And in China, you often see Kenyan "AA" or "AB" on offer, and some are even labeled "AA TOP". What do these mean, and are the differences between them big?

First, you need to know that coffee beans are an agricultural product, and product quality can be good or bad, so every coffee-producing country establishes a set of classification and grading systems for coffee beans. The purpose is to produce homogeneous commercial lots that meet established quality standards, thereby promoting a fair pricing system.

Kenya is no exception. At present, Kenya grades coffee according to bean size as well as shape, color and density. Generally, bean size and quality are used as indicators, divided into 8 grades: AA, AB, PB, C, E, TT, T and MH/ML. "AA" and "AB" are two of them, and these two grades are also the most common in China.

In Kenya, the main coffee varieties planted are SL28, SL34, Batian, K7 and Ruiru11. These varieties all share one common trait: large coffee beans, so in theory, the larger the bean, the higher the quality.

AA-grade coffee beans are 17-18 screen size, with good density; they are recognized locally as high quality, with an elegant mouthfeel and flavor. AB-grade coffee beans are 16-17 screen size. Although AB-grade beans are not as high in quality as AA grade, they are more affordable, and because their output is the highest, about 40% of coffee is AB grade, they are very popular.

In addition, the country has two distinctive bean-shape grades. One is round green bean Peaberry (PB), which refers to a coffee fruit that does not contain the usual two flat beans but only a single round bean. The other rather special bean shape is Elephant bean (grade E); this kind of bean is formed when two coffee beans become entwined during development, forming one very large coffee bean, with a screen size of 21 or above. Both of these beans are abnormally developed special coffee beans. In Kenyan coffee, only 5% is Peaberry (PB), and Elephant beans (E) are even rarer, so they are relatively scarce on the market and sell at a higher price.

C-grade coffee beans are 12-14 screen size, smaller in size. TT-grade coffee beans are light beans sorted out from E, AA and AB grades through an airflow separator, while T grade is defective beans selected from C-grade coffee beans, so neither belongs to the specialty coffee grade. MH/ML coffee is considered low-quality coffee beans, usually containing some underripe and overripe beans, so it is not exported and is only sold domestically.

However, the size of a coffee bean cannot directly determine whether the coffee tastes good or bad, so some Kenyan coffee exporters or green bean traders use their own set of coffee grading methods to grade exported coffee a second time. They mainly divide it by cupping score into "TOP", "Plus (+)" and "FAQ". However, this grading is not officially certified by Kenya, and because each merchant's standards are different, it can only serve as a reference; the specific result still depends on the actual performance of the coffee beans.

Moreover, in the early days, coffee was only introduced to Kenya during the British colonial period, and Britain developed the coffee economy during the colonial period, which made Kenya's entire system lean toward more refined management. In terms of coffee selection and breeding, grading and processing methods, it far surpassed many coffee-producing countries at the time. Therefore, generally reaching the AA and AB grades is already recognized locally as having high-quality mouthfeel and flavor.

Best Coffee currently has only one Kenyan coffee, and that is the K72 washed coffee beans produced by the Asali Processing Plant in the Thika region, using the common Kenyan SL28 and SL34 varieties, AA grade. Because these beans are plump and round, and to highlight the solid, bright fruit acidity of Kenyan coffee, Best Coffee uses a light roast; when brewed, it has notes of cherry tomato and smoked plum, juice-like acidity, and a crisp, soft mouthfeel.