There are numerous green bean flaws, some of which are more obvious than others. We are all familiar with the appearance of a stick or stone. Ricardo walked me through the two difficult-to-identify basic flaws—full black and full sour—as well as five common secondary problems.

Full black and partial black beans

Full black beans are a primary defect, while partial black beans are a secondary one. The beans are brown or black and shriveled, and the crack is too open. Causes include overfermentation, overripe cherries, and not enough water during cherry development.
Full black beans are a primary defect; partial black beans are a secondary defect. Credit: Angie Molina Ospina

Full-sour and partial-sour beans

Full-sour beans are a primary defect, while partial-sour beans are a secondary defect. They are a light to dark brown. These defects are caused by too long a wait between picking and depulping, an overly long fermentation process, or storing the beans while they have too high a moisture content.

Full-sour beans are a primary defect; partial-sour beans are a secondary defect. Credit: Angie Molina Ospina

Broken, chipped, or cut beans

This is a secondary defect, normally caused by the depulping machine.

Beans are broken by the depulping machine. Credit: Angie Molina Ospina

Insect Damage

Another secondary defect is caused by coffee pests: the coffee beetle borer, the white stem borer, the coffee bean weevil, and so on. Coffees damaged by the coffee beetle borer (la broca) tend to be sour and earthy.
Insect damage, probably from la broca. Credit: Angie Molina Ospina

Unhulled Beans

Unhulled beans are a secondary defect. It leads to an astringent, bitter cup. What’s more, the hull can become burned during roasting, damaging other beans in the process

credit : perfectdailygrind.com