Defects & AfflictionsGreen Coffee Glossary
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Berry Borer Beetle/Broca
An insect that invades the cherry to lay eggs. The berry borer beetle has an immunity to the caffeine that acts as a deterrent to many insects. Its points of entry and exit can in turn expose the bean to other damage. The berry borer beetle may kill the seed embryo and introduce off flavors to the cup. In appearance, insect damage from the borer beetle is characterized by at least one, but often many, small holes in the bean itself.
Black (Full or Partial)
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.
Pieces of dried parchment or cherry skin can be left on the coffee bean or included loose with the packed beans due to poorly calibrated hulling/depulping equipment and insufficient sorting. May increase the risk of a fire during roasting.
A hulling error, which leaves the full husk of the dried coffee skin and parchment on the seed.
Under drought conditions, green coffee beans can become withered/wrinkled and/or have a lower density, and can negatively affect sensory quality.
A low density, secondary defect, sometimes an immature seed, which can negatively affect cup quality. Floaters may be sorted by cherry flotation and/or by channel during washed coffees processing.
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.
Immature / underripe beans are usually smaller in size compared to other beans and curl at the tips to a slight u-shape.
Insect Damage (Severe/Minor)
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 hulling error where some beans are found still fully or partially covered in parchment due to poorly calibrated dry mill equipment. It can negatively impact flavor and increase the risk of fire during roasting.
Potato Taste Defect
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.
A coffee seed that does not properly brown during the Maillard stage of roasting, appearing much paler in comparison to its counterparts. Quakers are only identifiable once the coffee has been roasted, and are sometimes associated with immature coffee.
A less severe classification of green coffee defect according to the SCA and CQI. Specialty coffee may show a varying number of secondary defects, depending on which defect, in order to be classified as specialty grade green coffee.
Shells or “Elephant Ears”
A developmental anomaly caused by false polyembryony. The coffee bean develops into two separate halves, one tucked inside the other, which come apart easily and may roast unevenly.
Sour (Full or Partial)
A defect that may be caused by too long a wait between picking and depulping, an overly long fermentation process, or storing the coffee beans while they have too high a moisture content. Full sour is a primary defect, while partial sour is a secondary defect.
A sensory fermentation defect that emits an acetic or briny aroma and flavor due to dirty fermentation tanks or unstirred pockets in the slurry.
A developmental anomaly where the coffee cherry produces an extra seed, or in extreme cases, multiple extra seeds, caused by polyembryony.
These defects are often the result of drought damage, and cause the green been to look shriveled, like a raisin.