A primary defect affecting green coffee which partially or fully blacken the seed. Causes may include frost damage or fungus damage, severe overripening, moisture damage, fermentation errors, and other factors, and can have a significant negative impact on cup quality.

A secondary defect that may occur during post-harvest processing, increasing in frequency and severity with improperly calibrated equipment. Chipping, cutting, and/or breaking can happen both at the depulper (where the affected area will often become slightly discolored during fermentation) or at the dry mill during parchment hulling.

A hulling error, which leaves the full husk of the dried coffee skin and parchment on the seed.

Things which are not coffee, such as stones, sticks, or mechanical parts found in coffee samples. Foreign matter may accrue during harvesting and processing and is considered a primary defect.

Pre-processing damage to coffee caused by frost, which can result in a damaged cherry and blackened seed.

A primary defect caused by the growth of fungus on the seed. It may occur as the wet coffee dries, particularly if it is not turned frequently to promote even drying and good airflow. It is possible to spot some fungus visually, while some microbially damaged coffee remains latent until roasting, like the potato taste defect. If an infection is particularly bad, brownish spores may appear on the surface of the seeds. Black lights can also be used to spot some fungus damage, but may also return positives for other types of anomalies.

Insects, like the coffee berry borer, will burrow directly into the seed, leaving small visible holes. CQI recommends minor insect damage classified as up to three holes, while severe insect damage indicates there are more than three separate perforations in the bean.

A taste defect resembling the flavor and aroma of raw potatoes, caused by the presence of pyrazines, likely the result of a bacterial infection of the coffee cherry. It is primarily detected after roasting, making it difficult to sort out during post-harvest processing. Most commonly found in Rwanda and Burundi, but also observed in the Democratic Republic of Congo, Uganda, Tanzania, Zambia, and Kenya.

Any damage to coffee that occurs while on the tree or immediately after picking. Main culprits may include insects, genetic flaws, disease, environmental factors, and human error.

A classification of green coffee defect according to the SCA and CQI. Coffee must show no primary defects in order to be classified as specialty grade green coffee. Primary defects are considered to have the greatest impact on cup quality, and include full black, full sour, foreign matter, dried cherry/pod, fungus damage, severe insect damage, and foreign matter.

Defects that occur during preparation of coffee at the wet mill or dry mill. These are generally the most commonly encountered defects, which are usually the result of some combination of human and mechanical errors.