tags: [] - coffee/geography/east-africa - coffee/green-beans aliases: - Kenya coffee grades - Kenyan grading system - Kenya AA AB grading created: 2026-05-10 updated: 2026-05-10

Kenya Coffee Grading Standards¶

Tags: #coffee/geography/east-africa #coffee/green-beans Aliases: Kenya coffee grades, Kenyan grading system, Kenya AA AB grading Related: Kenya | Regional Coffee MOC | Coffee Origins MOC | African Coffee Comparisons Status: ✅ Complete

Overview¶

Kenya grades coffee primarily by physical bean size, expressed as a screen number corresponding to the diameter of the hole (in sixty-fourths of an inch) through which a bean will just pass. The system, administered by the Kenya Coffee Board (KCB), assigns letter designations to size bands — AA being the largest and most visible premium grade — but screen size does not reliably predict cup quality. Kenya AB, which combines two screen sizes below AA, frequently produces comparable or superior cup scores to AA from the same factory or cooperative, and is widely regarded as the better-value purchase.

Grade Definitions¶

Grade	Screen Size	Description
E (Elephant)	Screen 20+	Exceptionally large beans; rare and often marketed as a curiosity
AA	Screen 17–18	Standard premium grade; most internationally recognised
AB	Screen 15–16	Combined grade; high volume; often comparable cup quality to AA
C	Screen 14	Smaller beans from lower altitudes or marginal areas
PB (Peaberry)	—	Single rounded bean per cherry; naturally occurring; distinct cup profile
TT	Screen 17–18	Light beans (low density) removed from AA grade by aspiration
T	Screen 14–15	Light beans removed from AB and C grades
MH	—	Mbuni heavy — dry-processed (natural) coffee of higher density
ML	—	Mbuni light — dry-processed (natural) coffee of lower density

Mbuni grades (MH and ML) are dry-processed coffees produced when cherry is not delivered to a wet mill. They are considered lower quality than washed grades and are typically destined for commercial blends.

The AA vs AB Question¶

Kenya AA commands the highest price at the Nairobi Coffee Exchange (NCX) auction and in the international specialty market. The premium reflects brand recognition and market convention, not a consistent quality advantage. Several studies and cupping comparisons have found that AB from a premium washing station or cooperative often scores within 0.5–1 SCA point of AA from the same producer. AB beans are simply smaller — not less flavourful. For buyers seeking value, AB lots from well-regarded factories in Nyeri or Kirinyaga routinely outperform AA lots from lower-quality sources at lower cost per kilogram.

Marketing and Auction System¶

All washed Kenyan coffee is sold through the NCX weekly auction in Nairobi. The Kenya Coffee Board provides a pre-auction catalogue that includes cup assessment scores and sample availability. Buyers — typically exporters acting on behalf of overseas roasters — bid against the catalogue lots. The auction model ensures price discovery and transparency but limits direct producer relationships; cooperatives and private estates increasingly seek direct-trade agreements for their top lots, bypassing the auction for premium production.

Grading and Cup Quality Relationship¶

Screen size is a proxy for altitude and variety performance, not a direct measure of flavour. The correlation between grade and quality arises because AA-sized beans tend to come from higher altitudes (where slower maturation concentrates flavour compounds) and from farms with better management. However, this correlation is not absolute. A small-farm natural or an AB peaberry from a well-managed Nyeri cooperative can comfortably outscore an AA from a lower-altitude or commercially managed estate.

Key Facts¶

Kenya uses a screen-size grading system administered by the Kenya Coffee Board (KCB)
Primary grades: E (screen 20+), AA (17–18), AB (15–16), C (14), PB (peaberry)
TT and T grades are low-density beans removed from AA and AB by aspiration
MH and ML are dry-processed (natural) commercial grades
AA commands the highest market price but does not reliably deliver better cup quality than AB
All washed coffee is sold through the Nairobi Coffee Exchange (NCX) weekly auction
Cup score, not grade alone, is the reliable predictor of specialty quality

References¶

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