Coffee Grade Classification
Coffee grading evaluates green bean quality by screen size (measured in 1/64-inch increments, e.g. screen 18 = 18/64 inch), defect count per 300 g sample, moisture content, and altitude. Specialty grade requires at most 5 Category 1 defects and zero quakers. Ethiopia uses Grade 1-5, Kenya uses AA/AB/PB/C/E, Colombia uses Excelso/Supremo. Grading determines price and export eligibility and helps roasters predict roast development.
Background & Context
Coffee grade classification is the system of physical quality assessment applied to green (unroasted) coffee before cupping evaluation. Grading evaluates defect count, bean size (screen size), moisture content, and sometimes altitude — providing a standardised shorthand for lot consistency that allows traders to compare lots across origins without tasting them. The major grading systems are: Ethiopia (Grade 1–5 by defect count per 300g, Grade 1 = ≤3 defects), Kenya (AA/AB/C/PB by screen size, AA = screen 18+), Colombia (Supremo screen 17+, Excelso screen 14–16), Brazil (Type 2–8 by defect count, Type 2 = 4 defects), and Guatemala (SHB = Strictly Hard Bean = grown above 1,350m). Defects are categorised as primary (full black, full sour, stones — always penalised) or secondary (partial black, partial sour, shell — subject to threshold).
Practical Use
For practical buying decisions, grade is the pre-cupping filter. A Grade 1 Ethiopian lot from Yirgacheffe or Guji guarantees low defect density and implies selective hand-picking — increasing the probability of a high SCA score, but not guaranteeing it. Kenya AA guarantees bean size (important for roast uniformity since smaller beans roast faster than larger ones) but not cup quality — some Kenya AA lots score below 80 SCA. The key principle: grade describes physical consistency; cupping evaluates flavour quality. Both are necessary for a confident purchasing decision. Request grade certification and cupping report together, and verify that the cupping was conducted under SCA protocol by a Q Grader.
Related Terms
Related terms: Coffee grade, Cupping, Specialty coffee, Kenya coffee, Ethiopia coffee, SCA score.