Coffee Defects

A practical reference to green coffee defects, their possible causes and why defect terminology must be interpreted carefully.

Primary and secondary defects

Coffee standards often distinguish more serious defects from less consequential ones. The exact classification depends on the grading system used.

Common physical defects

Examples include black beans, sour beans, insect damage, broken beans, chipped beans, shell-like forms and foreign material. Defects can originate before harvest, during processing, drying, milling or storage.

Quakers and roasting

A quaker is a pale roasted bean that can result from underdeveloped or otherwise abnormal green coffee. It is usually discussed as a roasting/sensory issue rather than a single formally universal green-bean defect category.

Cause is not always obvious

A visible defect does not necessarily reveal its precise cause. Accurate diagnosis requires knowledge of harvest, processing, drying, storage and roasting conditions.

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Coffee Knowledge presents technical subjects as an educational reference. Terminology, grading systems and production practices can vary by country, producer, equipment and commercial context.