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Kenya AA vs. AB Coffee: What the Grade Tells You

Understand Kenya AA and AB coffee grades, how screen sorting differs from cup quality, and what to ask before paying more for a bag.

By Edward MillerPublished March 19, 2026Updated October 24, 20264 min read

Quick Answer

Kenya AA is a larger flat-bean grade; AB is a smaller flat-bean grade. The letters describe the physical sorting of green coffee, not a cup score or a promise that AA will taste better. Use the grade to understand the beans, then choose the particular lot, roast and flavor description that suit what you want to drink.

Workers tending pale coffee seeds on raised drying tables beside water channels and a green hillside.

On This Page8 Sections

Start with the Green Bean, Before Roasting

AA and AB are assigned before roasting. After the parchment layer is removed, a mill sorts the green coffee by physical characteristics such as size, weight and shape. Kenya's embassy explanation of its coffee industry distinguishes this mechanical grading from the assessment of raw, roasted and brewed characteristics.

Picture a sieve: an opening retains beans too large to pass through and lets smaller ones fall through. Another screen can divide the passing fraction again. The International Trade Centre's Coffee Exporter's Guide, Box 11.1, explains this size-sorting role; ISO 4150's official abstract describes size analysis using laboratory test sieves.

The grade on a roasted bag comes from that earlier stage. The beans' appearance also reflects roasting, so lining up two retail bags on your counter does not recreate the original screen sorting.

AA and AB Are Part of a Wider Sorting System

The Nairobi Coffee Exchange's current grade description lists AA at screen 18 and AB at screen 16–17. The wider system also distinguishes shape and density:

Kenyan coffee grades describe different physical traits

Kenyan coffee grades describe different physical traits
Label	What the physical category describes
AA	A larger flat-bean fraction; the exchange lists screen 18.
AB	A smaller flat-bean fraction; the exchange lists screens 16–17.
PB	Peaberries, separated as rounded single seeds.
TT	Light-density beans separated from other fractions by air.

The exchange also lists E for very large beans. These categories are not simply steps down one flavor ladder: size, shape and density describe different traits.

A screen number identifies a sieve opening, not a score out of 100 or the identical diameter of every bean in a bag. A fraction contains a range of sizes, and passing depends on the opening and the sieving method.

Passing a Screen Is Not the Same as Passing a Tasting

A size grade tells a buyer about the green beans being handled and roasted. Tasting asks what the prepared coffee smells and tastes like, and how positively those qualities are judged.

The Specialty Coffee Association's Coffee Value Assessment separates physical assessment, including size and defects, from sensory description and impressions of quality. Origin and other information beyond the sensory assessment have their own place too. Our specialty-coffee explainer covers that broader evaluation.

Use the Label to Ask Better Questions

Start with the cup you want. Suppose two imaginary listings come from the same named washing station:

AA, washed, citrus and blackcurrant
AB, washed, cocoa and dried fruit

Those flavor notes describe the fictional coffees, not flavors assigned to the grades. If you want a cocoa-led cup, the AB description gives you a reason to consider that bag rather than paying more for the AA initials.

Ask the roaster which lot they are selling, how it was roasted and which brew method they recommend. If you want to compare AA and AB, look for the same producer, harvest and processing method with comparable roast styles. Otherwise, you are choosing between two finished coffees with several differences, rather than isolating bean size.

A personal note: An AA label would catch my attention, but I would still want the roaster to tell me why they chose that particular coffee. A note about its character gives me something I can connect with the cup I want to drink. The variation in published screen descriptions also makes me wary of pretending the letters explain everything. I find the label more useful as the start of a conversation about a lot than as a reason to stop asking questions.

A Higher Price Needs More Context Too

The exchange associates some grades with stronger demand and premium markets. An individual retail offer also depends on the lot, availability, package size and the business selling it. The letters alone do not explain every price difference.

Compare the net coffee weight and total you would pay, including delivery where it differs. Then ask what the premium buys you: a particular lot, a flavor you want to explore or useful sourcing information. Choose the offer that makes sense for the coffee you want, rather than assuming every AA bag deserves a higher price than every AB.

Keep the Country Attached to the Grade

This is Kenyan grading terminology. A similar letter or number on coffee from another origin can belong to a different system. Check the named country's grading description before treating the labels as equivalent.

Our coffee-bag reading guide explains the other fields to examine, including lot identity, processing and roast.

Sources

Screen-description note: The linked 2019 Kenyan grading schedule describes AA as passing screen 21 and retained on 18, with screen 18 listed as 7.2 mm (0.28 in), and AB as passing screen 18 and retained on 16. The AFA brochure below instead describes AB as passing 18 and retained on 17; the exchange's current explainer lists 16–17. These are different published descriptions, not one harmonized exact cutoff. For a purchase where the exact cut matters, request the lot's screen distribution and the grading specification used.