Kenya AA vs AB: Understanding Kenyan Coffee Grades
Kenya AA vs Kenya AB: Understanding Kenyan Coffee Grades
If you have ever bought Kenyan coffee, you have probably seen labels such as AA, AB, PB, C, E, or TT printed on the bag. But what do these letters actually mean?
And why does one Kenyan coffee say AA while another says AB? More importantly, does AA automatically mean better coffee? The answer is more interesting than you might expect.
Kenya has one of the most recognizable coffee grading systems in the world. Unlike a simple quality ranking, the system uses physical characteristics of the green coffee beans—particularly size, shape, and density—to classify different grades.
Understanding this system can help you read a bag of Kenyan coffee more intelligently and appreciate what goes into producing the coffee in your cup.
What Does Coffee Grading Mean?
Before comparing AA and AB, it is important to understand what coffee grading actually is. Coffee grading happens after coffee cherries have been harvested, processed, and dried.
The resulting green coffee beans are prepared for export and separated according to different characteristics.
In Kenya, the dry-milling process separates coffee into grades based on factors including:
- Bean size
- Bean shape
- Density
Kenya's Agriculture and Food Authority identifies grades including E, AA, AB, PB, C, TT and T.
So when you see AA on a bag of Kenyan coffee, it is not simply a score of “excellent.”
It is a classification that tells you something about the physical characteristics of the green beans.
This distinction is important. Coffee grade and coffee quality are related, but they are not the same thing.
Why Are Coffee Beans Measured by Size?
You might wonder why coffee producers and buyers bother separating beans by size in the first place.
One reason is consistency.
Coffee beans of different sizes can respond differently during roasting because they do not necessarily absorb heat at the same rate.
Separating beans into relatively uniform groups can therefore help roasters develop more consistent roasting profiles.
Screen sizing also provides buyers with a standardized way of describing the physical characteristics of green coffee.
However, bean size alone does not determine how good a coffee will taste.
A smaller bean can produce an exceptional cup, while a larger bean is not automatically superior.
Coffee professionals therefore look beyond size to factors such as:
- Variety
- Growing environment
- Processing
- Density
- Defects
- Storage
- Cup quality
- Roasting
Coffee grading systems also differ from country to country, so an “AA” designation in one origin should not automatically be interpreted as equivalent to an “AA” somewhere else.
What Is a Coffee Screen Size?
To understand AA and AB, we need to understand screen size. Coffee screens are essentially standardized sieves used to separate green coffee beans according to their physical size.
The numbers refer to the size of the openings in the screen. In the traditional system, screen sizes are measured in 64ths of an inch.
For example:
Screen 18 = 18/64 inch
Screen 17 = 17/64 inch
This might sound complicated, but the basic idea is simple:
The higher the screen number, the larger the opening—and generally the larger the bean that can pass through it.
This is how Kenyan coffee can be separated into different size categories.
What Is Kenya AA Coffee?
AA is one of Kenya's most recognized coffee grades.
According to Kenya's Agriculture and Food Authority, AA beans are approximately 7.2 mm in diameter and are retained on the relevant screen during grading. In the Kenyan system, AA corresponds to beans passing through screen 21 and being retained on screen 18.
The term is commonly expanded as: AA — Above Average
But this name can be misleading if interpreted as a direct sensory quality score. AA primarily tells us about the physical grade of the green coffee.
It does not tell us:
- How the coffee was grown
- Which variety produced it
- How carefully the cherries were harvested
- How it was processed
- How fresh it is
- How it was roasted
- How it will taste
Those factors still matter.
What Is Kenya AB Coffee?
AB is another important Kenyan coffee grade. AFA describes AB beans as slightly smaller than AA, approximately 6.8 mm in diameter, corresponding to beans passing through screen 18 and being retained on screen 17.
AB is commonly referred to as: AB — Average Bean
Again, the name should not be interpreted as: “AA = excellent, AB = average quality.”
That would oversimplify the Kenyan grading system. The distinction is primarily about bean size and physical classification. And AB is far from being an insignificant category.
In Kenya's 2021/22 production data, AB accounted for approximately 40.9% of clean coffee grades, compared with approximately 21.7% for AA.
So AB is not some rare or inferior leftover category. It is a major part of Kenyan coffee production.
Kenya AA vs AB: What's the Physical Difference?
Here is the simplest way to understand it:
| Grade | Approx. size | What it means |
|---|---|---|
| AA | 7.2 mm / 18/64" | Larger flat beans |
| AB | 6.8 mm / 17/64" | Slightly smaller flat beans |
| PB | 4.76 mm / 12/64" | Peaberry |
| C | 3.96 mm / 10/64" | Smaller beans |
| E | 8.3 mm / 21/64" | Very large “Elephant” beans |
These classifications come from Kenya's grading system.
Notice something important: AA and AB are only one part of a much larger grading system.
What Is Kenya PB?
Another grade you may encounter is PB.
PB stands for Peaberry. A normal coffee cherry usually develops two seeds, with each seed having one relatively flat side.
Sometimes, however, only one seed develops inside the cherry.
That single seed becomes rounded rather than having the typical flat-sided shape.
This is called a peaberry.
Kenya therefore classifies peaberries separately from the flat-bean AA and AB grades.
Importantly, PB does not simply mean “small coffee.”
It describes a different bean shape and development pattern.
What About Kenya E, C, TT and T?
The Kenyan system contains several other grades.
E — Elephant: These are exceptionally large beans.
AFA describes E beans as being retained on screen 21. The category can include very large beans and certain beans joined together.
C: C beans are smaller than the AB category.
TT: TT refers to light-density beans separated from AA, AB, and E grades through air extraction.
T: T represents very small beans and broken pieces.
The important lesson is that these letters are describing different physical characteristics, rather than providing a universal 1-to-7 quality ranking.
Does Bigger Mean Better?
This is where coffee grading becomes particularly interesting.
It is easy to assume:
Bigger bean = better coffee.
But that isn't necessarily true.
Coffee professionals have repeatedly pointed out that screen size alone is not a definitive measure of cup quality. Different coffee varieties naturally produce different bean sizes, and excellent coffees can come in smaller sizes.
Think about it this way.
Imagine two coffees:
Coffee A
AA beans
Average processing
Average storage
Average roasting
Coffee B
AB beans
Excellent cherries
Careful processing
Excellent storage
Careful roasting
There is no rule saying Coffee A must taste better.
Coffee B could produce the more impressive cup.
That's why specialty coffee buyers ultimately evaluate the coffee itself, not just the grade printed on the bag.
So Why Does AA Often Cost More?
If AA doesn't automatically mean better flavor, why does it often command a higher price?
There are several reasons.
First, larger beans are commercially valued and traditionally attract stronger demand.
Kenya's AFA reports that AA attracts higher prices than other grades.
Second, buyers may specifically request particular grades for commercial and roasting purposes.
Third, AA has developed a strong reputation in the international coffee market.
That reputation itself influences demand.
But a higher price does not mean that every AA coffee will necessarily taste better than every AB coffee.
This is an important distinction for consumers.
Does AA Taste Different From AB?
This is one of the most common questions.
The honest answer is:
Not necessarily in a predictable way.
AA and AB are different physical grades, but the grade itself does not create a specific flavor profile.
You cannot reliably say:
“AA tastes like berries and AB tastes like citrus.”
That's not how the grading system works.
Flavor comes from a much larger combination of factors.
What Actually Creates the Flavor of Kenyan Coffee?
To understand the cup, we need to move beyond the letters.
1. Variety
Different coffee varieties have different genetic characteristics.
Kenya is particularly known for varieties such as SL-28 and SL-34, alongside other varieties including K7, Ruiru 11, and Batian.
These varieties can contribute to differences in the final cup.
2. Altitude
Much of Kenya's Arabica coffee is grown in highland environments.
Altitude affects temperature and the rate at which coffee cherries develop.
It is one of many environmental factors that can influence coffee characteristics.
3. Soil
Many Kenyan coffee-growing areas have fertile volcanic soils.
Kenya's AFA notes that coffee is grown in volcanic-soil regions around areas such as Mount Kenya and the Aberdare ranges.
4. Climate
Rainfall, temperature and seasonal conditions influence the development of coffee cherries.
Different regions of Kenya therefore produce different expressions of Kenyan coffee.
5. Harvesting
Quality starts with the cherry.
AFA identifies the harvesting of uniformly ripe cherries, followed by prompt sorting and processing, as an important part of Kenyan coffee quality control.
6. Processing
Processing has a major influence on flavor.
Kenyan coffee has historically been strongly associated with washed processing, which can produce clean and vibrant cups.
But natural and experimental processing are also becoming increasingly visible within Kenya's specialty coffee sector.
7. Roasting
Even an exceptional green coffee can be poorly represented by an unsuitable roast.
Roasting determines how the coffee's acidity, sweetness, body, and aromatic characteristics are expressed.
This is why the same green coffee can produce very different results under different roasting approaches.
8. Brewing
And finally, the coffee reaches you.
Your:
- Grind size
- Water temperature
- Coffee-to-water ratio
- Brewing time
- Brewing method
can all influence what you taste.
So the journey from AA or AB to your cup is much longer than the grading label suggests.
Why Is Kenyan Coffee Famous for Its Acidity?
Kenyan coffee has a distinctive reputation for bright acidity, aromatic complexity, and intense cup character.
Kenya's AFA describes Kenyan Arabica as being recognized internationally for its vibrant acidity and intense cup profile.
In coffee, acidity isn't necessarily a flaw.
Think of the difference between:
- a flat glass of fruit juice
- and a fresh, vibrant citrus fruit
The latter has brightness and energy.
Similarly, acidity can give coffee structure and liveliness.
Depending on the coffee, Kenyan cups can remind you of:
blackcurrant, berries, citrus, stone fruit, wine or other bright fruit characteristics.
But these are sensory descriptions, not ingredients added to the coffee.
Why Does Bean Size Matter to a Roaster?
This is one area where AA versus AB becomes particularly practical.
Different bean sizes and densities can respond differently to heat.
A roaster therefore needs to understand the physical characteristics of the green coffee when designing a roasting profile.
More uniform bean sizes can make it easier to achieve consistent heat application across a batch.
Perfect Daily Grind's discussion with coffee professionals notes that bean size can affect heat transfer during roasting, although the difference between AA and AB is not necessarily dramatic.
So the grade isn't only useful to buyers. It is also information for the roaster.
AA vs AB: What Should a Coffee Buyer Actually Look At?
If you're choosing between two Kenyan coffees, don't stop at the grade.
Ask these questions:
Where is it from?
A country is a starting point.
A region tells you more.
A farm, cooperative or washing station can tell you even more.
Which variety?
SL-28?
SL-34?
Batian?
Ruiru 11?
How was it processed?
Washed?
Natural?
Experimental?
When was it roasted?
Freshness matters.
What is the roast level?
Light?
Medium?
Dark?
What does the coffee actually taste like?
Look for the roaster's tasting notes.
How was the coffee evaluated?
If you're buying specialty coffee, cup quality is ultimately much more informative than bean size alone.
A Simple Way to Remember Kenyan Coffee Grades
If all of this sounds complicated, remember this:
AA: Large flat beans
AB: Slightly smaller flat beans
PB: One rounded seed instead of the usual two
E: Very large beans
C: Smaller beans
TT: Light-density beans
T: Very small or broken beans
And the most important rule:
A grade tells you something about the bean. It doesn't tell you everything about the coffee.
Why This Matters When You Buy Kenyan Coffee
Understanding grades changes the way you look at a coffee bag.
Instead of seeing:
KENYA AA
and assuming that the letters tell you everything, you can now ask:
Where was this coffee grown?
Which variety was used?
How was it processed?
How was it roasted?
What does it taste like?
Who produced it?
Those questions take you much closer to understanding the coffee itself.
Discovering Kenyan Coffee at Kaawa House
At Kaawa House, we believe that knowing where your coffee comes from makes every cup more meaningful.
Our Kenya AB @https://kaawahouse.com/products/kenya-ab-arabica is part of our collection of East African coffees, alongside origins such as Uganda, Ethiopia, Rwanda, and Tanzania.
And now, when you see AB on our Kenyan coffee, you'll know exactly what it means.
It isn't a statement that the coffee is “average.”
It tells you about the physical grade of the green beans.
The real quality story is much bigger:
The variety.
The altitude.
The soil.
The harvest.
The processing.
The roasting.
And finally, the cup.
Because great coffee isn't defined by two letters on a bag. It is defined by the journey behind them.