What are Coffee Bean AA and AAA Grades Based On? What Are Their Characteristics?

As observant coffee enthusiasts may have noticed, most commercially sold coffees carry the "AA" suffix. This is particularly common with coffee beans from Kenya. Kenya Nyeri AA, Kenya Kirimiri AA, and so on.

It's not just Kenya—coffee beans from countries like Tanzania and Uganda also carry the same AA suffix. So, the question arises: What does AA mean? Why do these countries emphasize AA for their beans?

What Does the AA Suffix Mean for Coffee Beans?

The "AA" suffix on coffee beans actually represents a grade level for those beans. Because coffee beans are not industrial products, their quality varies significantly. Therefore, to standardize quality, a system is needed to distinguish between superior and inferior beans. This system is what we call grading. So, when we see coffee beans from certain countries followed by the letters "AA," we can know that country grades their coffee beans by size.

Here, we need to understand two key points: First, coffee bean grading systems are not based solely on size—there are other grading methods based on defects, altitude, and more. The specific application varies according to different countries' national conditions. FrontStreet Coffee will elaborate on this next time.

Second, not all size-based grading systems use uppercase English letters as identifiers. Because identifiers like AA and AB are part of the unit system developed by the British, most coffee-producing countries use these units because they were formerly British colonies. For example, Colombia also grades coffee beans by size, but uses "Supremo" and "Excelso" as their grade identifiers.

Ultimately, Kenya is the most famous coffee-producing region for using size-based grading because the Kenyan government takes the coffee industry extremely seriously, maintaining very strict requirements for coffee quality! So now, FrontStreet Coffee will introduce Kenya's size-based grading system!

Kenya Coffee Bean Grades

AA: Bean size between 17-18 screen.

AB: Bean size between 15-16 screen.

C: Grade C coffee beans are between 12-14 screen. Due to their small size, these beans are generally not classified as specialty grade.

PB: Rare round-shaped green beans, short for Peaberry.

E: Full name Elephant, referring to elephant beans. It's important to note that the "elephant beans" mentioned here do not refer to the elephant bean varieties in coffee species (Maragogipe, Pacamara), but rather to special coffee beans that developed abnormally, similar to peaberries. These beans are formed when two coffee beans become intertwined during development, creating what appears to be a single, very large, swollen coffee bean. They exceed 18 screen and are extremely rare.

TT: Grade TT consists of lightweight beans that have been blown out from AA and AB grade beans using air screeners.

T: Grade T consists of lightweight beans that have been blown out from Grade C beans using air screeners.

MH/ML: These two grades, due to their lower quality, are not processed using the Kenyan washed method. They are typically consumed domestically and not exported outside Kenya.

The Limitations of Size-Based Grading

The above represents Kenya's official national grading system, where it's clear that AA represents the highest grade in Kenya's classification system, meaning the best quality. However, FrontStreet Coffee recently shared an evaluation article titled "Does Coffee Bean Flavor Relate to Size?" which detailed the drawbacks of size-based grading systems—that they have too many loopholes.

Coffee bean size does not directly affect the quality of coffee flavor! Let's take an example commonly mentioned by coffee professionals: When the same coffee variety is grown at 900 meters and 1700 meters respectively, even if the harvested beans are the same size, the coffee from 900 meters will definitely not taste as good as that grown at 1700 meters. Because the growing environment is one of the main factors influencing flavor formation during coffee bean development.

Kenya's Quality-Based Grading System

In an era when bigger was considered better, such grading systems were naturally the mainstream approach. Most traditional coffee-producing countries basically adopted size-based grading methods. However, when the concept of specialty coffee emerged, people became aware of the key factors influencing bean flavor formation, leading to the development of entirely new grading systems. Kenya didn't fall behind either—local coffee research institutions and green coffee traders use their own coffee grading methods to conduct secondary grading of Kenyan AA and AB grade coffees.

This system is called the "Coffee Bean Quality Grading Procedure" (Kenyan Classification Procedure by Quality Assessment) and was developed by the Kenyan Coffee Research Foundation! This procedure provides a comprehensive evaluation based on three aspects: green bean quality, roasted bean quality, and cupping quality.

TOP, Plus (+), and FAQ are identifiers for this secondary grading. When beans receive corresponding grade scores, these identifiers are added to the coffee bean's original grade, such as Kenya AA TOP, Kenya AA+, etc. They indicate beans with outstanding performance within AA or AB grades, while FAQ represents beans with slight defects that don't affect flavor.

Finally, it's important to know that because this system is not officially certified by Kenya, most Kenyan beans available on the market today still primarily use conventional size-based grading (AA, AB) as the mainstream approach.

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