Full Black / Partial Black

Full Black

Partial Black

Español: Negro completo / parcial
Français: Fève noire / Fève demi-noire

Full Black is a Primary (Category 1) defect: 1 black bean (> 50% damaged) = 1 full defect
Partial Black is a Secondary (Category 2) defect: 3 partially black beans (< 50% damaged) = 1 full defect
Black beans are identified by an opaque color; however, Robusta immature beans tend to oxidize and grow dim — from bright green to grey-greenish, grayish, gray-brownish, dark brown- blackish and finally deep black. As a result, you must assess whether or not coloring continues beneath the skin. If only the skin is dark, the bean is classified immature. If the bean itself is discolored then it is either a partial or full black defective bean. See also IMMATURE, UNRIPE
Cup: moldy, soil, ferment, stinker, fishy and or phenolic taste
Consideration: Ochratoxin A (OTA) risk
Cause(s): AGRICULTURAL: Blackening may result from die back oxidation of green beans, disease-related bean injury (CBD, anthracnose, etc.), insect damage and / or frost. In most cases, pigmentation is associated with micro-organism activity (aerobic and anaerobic over-fermentation)
Remedies: AGRICULTURAL: Prevent the development of black beans with good plant nutrition and moisture, proper aeration and drainage. Selectively pick ripe cherries and always avoiding contact with soil, contaminated tools or harvesting utensils.
PROCESSING: Black beans begin as injured or contaminated beans and are usually slightly less dense than unaffected beans, therefore may be removed by screening and density sorting.   The most effective method is to remove using an electronic color sorting machine or manual (hand) sorting.