Defect

A defect is a flawed bean or foreign object in a lot of green coffee that hurts quality. Defects come from every stage: bad cherries, processing mistakes, drying problems, pests, and storage. Common ones include the quaker (an underripe bean that will not brown), sour or fermented beans, black beans, insect-damaged beans, broken or chipped beans, and stones or sticks.

Why it matters: defects are the backbone of coffee grading. In the SCA and Q grading system, graders count defects in a 350 gram sample and split them into Category 1 (primary, more severe, like full black or sour beans) and Category 2 (secondary, like broken beans or husk). To qualify as specialty, a sample must have zero Category 1 defects and only a small number of Category 2.

In the cup, defects show up as the off-flavors specialty coffee tries to avoid: sour, fermented, musty, phenolic, or harsh peanutty notes. Even a handful of bad beans can taint a whole batch, which is why hand sorting and careful drying matter so much.