Kenya AA is a screen size, not a flavour grade

On Kenyan bags, AA and AB look like a quality ladder. They are not. After parchment is hulled, mills sort green coffee through metal screens with holes of different sizes. AA is the larger fraction commonly tied to screens 17 and 18; AB is the next band, often screens 15 and 16. The letters record how many beans stayed on those sieves — a physical sort, not a cupping score.

Other marks belong to the same family of mill sorts, not a flavour menu. PB means peaberry: a single, rounder seed in the cherry instead of the usual pair, separated more by shape than by the AA sieve. E, sometimes called elephant, is a still larger screen and less common on café shelves. Older or secondary lots may carry other letter codes from the same grading system. None of these letters promises blackcurrant, tomato, or any other Kenya shorthand you have read on a menu.

What moves the cup sits beside the grade line. A washing station or cooperative, a county such as Nyeri, Kirinyaga, Murang'a or Embu, a variety such as SL28, SL34, Ruiru 11 or Batian, the year's harvest, and how evenly the classic washed process was managed — all of that can outweigh whether the bag says AA or AB. A carefully prepared AB lot can taste cleaner and sweeter than a rushed AA from a mixed delivery. Read the grade the way you already read bean size on other origins: useful, incomplete.

If a bag only says Kenya AA, you still know too little to guess the cup. Look for the station or estate name, the region, the harvest year, and the process. AA tells you the beans were large enough to stay on a certain sieve. The rest of the label is where the coffee actually lives.