Coffee Bean Defects

Defects in green coffee beans are caused by various reasons. Careless processing, improper harvesting, improper moisture content during storing, or any other green bean property including physical defects, will have negative effect on the quality and the taste of the coffee produced.

Antestia Damage from the Antestia bug, resulting in coffee beans ranging from slightly discolored to almost entirely black and shriveled.

Bits Pieces of coffee beans crushed during processing.

Black Beans Black or very dark, unroasted beans. Black beans typically result from harvesting immature cherries or by harvesting dead cherries that fall naturally from the tree. Black beans can also result from exposure to water, heat and insect-damage. Unroasted coffee beans with more than 25% black, deep blue, or dark brown surface area, can be considered black beans.

Blotchy Irregular greenish, whitish or yellowish patches on unroasted coffee beans. Blotchy beans may result from incomplete or uneven drying during processing.

Boat-Shaped Beans with ends that curve upwards like a boat.

Bullhead An extra large coffee bean. Sometimes a peaberry that has not totally grown together.

CBB Damaged Coffee beans damaged by the Coffee Berry Borer. This pest, also known as Hypthenemus Hampei, is one of the most significant pest problems for coffee farmers. The CBB is a black two millimeter long beetle that bores holes through the seeds coffee cherries.

Crushed Crushed coffee beans most commonly result from improperly set or damaged pulping equipment. Coffee beans can also be crushed during mechanical separation of the beans from the husk, or during mixing in fermentation tanks.

Diseased Disease-damaged coffee beans. There are many coffee plant diseases that can damage a coffee crop, but most are caused by fungus (mold). The most prevalent coffee mold problems are Coffee Leaf Rust (CLR), which shows as yellow-orange blotches on the leaf, and Coffee Berry Disease (CBD), which lives in the bark of the tree and produces spores that attack the coffee cherries. CLR, CBD, and Coffee Berry Borer (CBB) are significant disease and pest problems facing the world’s coffee farmers.

Drought-Affected Ragged shaped, pale, and light weight unroasted coffee beans. Also called “droughty” or “flaky”.

Elephant Beans A cluster of two or more deformed beans that grow closely locked together, but sometimes separate during processing or roasting. Also called “ears” due to their often ear-like appearance.

Faded Unroasted coffee beans that have lost much of their original color, a characteristic of old crops and beans that were dried too rapidly. If stored too long before roasting, processed coffee beans slowly fade from green to pale yellow. Also called “soapy” or “bleached”.

Foxy Unroasted coffee beans with a brown or rust color. Foxy beans may result from faulty fermentation, improper washing, over drying, or by harvesting over-ripe cherries. Also called “brown”.

Moldy Unroasted coffee beans with a light green or white fur-like texture characteristic of mold. Roasted coffee beans affected by mold have a “musty”, or “moldy”, flavor.

Mottled Unroasted coffee beans with blotchy discolorations, associated with uneven drying during processing.

Musty Taste or aroma characteristic of mold. A musty characteristic is associated with drying the coffee too slowly or storing unroasted coffee in a damp environment. Monsooned and aged coffees may have a slightly musty flavor.

Over-Fermented Coffee allowed to ferment too long during wet processing. After de-pulping coffee cherries to remove the skin and some of the pulp, the separated seed still has a significant amount of pulp attached. The remaining pulp can be loosened by fermentation, allowing it to be washed away before drying. If fermentation is not stopped as soon as the remaining parchment is no longer slimy, and has a rough texture, the coffee may acquire oniony or sour flavors.

Pales Unroasted yellow coffee beans that stink when crushed or ground. Pales may result from drought or from harvesting immature coffee cherries.

Peaberry A single rounded bean from a coffee cherry which bears one bean instead of the usual flat sided pair of beans. Also known as “caracol”, “perla” and “perle”. Peaberries are frequently separated and sold as a distinct variety.

Pulper Nipped Wet processed beans that have been cut or bruised during pulping. Typically caused by damaged or improperly configured pulping equipment. Pulper cut beans usually show brown or black marks after processing. Discoloration develops by oxidation at the damaged areas and off-flavors may result. Pulper damaged beans roast unevenly, age rapidly, and are susceptible to damage by vapors, dust, and other adverse environments. Also called “blackish” or “pulper cut”.

Quaker Unripened coffee beans, often with a wrinkled surface; quakers do not darken well when roasted.

Ragged Coffee with a ragged appearance. Harvesting mature and immature cherries, or drought-affected cherries, can result in beans with a ragged appearance.

Shell A common defect, where coffee beans have a large cavity similar to a shell. While only a secondary concern, compared to defects such as stones, sticks, black beans, or sour beans, too many shells in a coffee sample is an indication of a lesser coffee grade.

Stinker A coffee bean that produce an unpleasant or foul taste when crushed or cut. Beans that get stuck in a pulper or fermentation tank too long may become stinkers. Stinker beans can spoil the taste of an otherwise good batch of coffee.

Under-Dried Beans with a moisture content above 12%. The final drying process should result in coffee beans with 10% to 12% moisture content.

Withered Wrinkled, undeveloped and light-weight coffee beans. Withered beans are typically the result of drought or poor husbandry.

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