Understanding Kenya's Grade System: AA, AB, and PB

Kenya grades its washed coffee primarily by bean screen size — a measure of the physical diameter of the green bean. Kenya AA is the largest screen (above 17/64 inch), commanding premium prices for its visual consistency. Kenya AB combines the next two size grades (AB = screen 15/16 and 14/64) into a single commercial grade. Kenya PB (Peaberry) is a naturally occurring genetic anomaly where a single round bean replaces the normal two flat-sided beans within a cherry.

Grade does not directly determine cup quality — the terroir, variety, processing, and factory management determine that. But AB, by combining two size grades, often creates a naturally blended lot that some buyers prefer for its more integrated, complex cup compared to the sometimes austere intensity of AA lots. Rungeto FCS's Kii AB is a prime example: a complex, layered lot that delivers the full Kirinyaga SL28/SL34 profile with exceptional balance.

Rungeto Farmers Cooperative Society

Rungeto FCS is one of Kirinyaga County's best-regarded cooperative societies, operating multiple factories — including Kii — across its membership territory on the slopes of Mount Kenya. The cooperative manages post-harvest processing, milling, and export for hundreds of smallholder member-farmers who each contribute small volumes of cherry to the collective system. Kii factory's management team oversees the double-washed fermentation and raised-bed drying that produces the clean, structured cup profile Rungeto's lots are known for in specialty markets across Europe and North America.

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