Foreign Matter

Organic Foreign Matter

Inorganic Foreign Matter

Español: Materia extraña, impurezas
Français: Matière étrangère

Foreign matter is a Primary (Category 1) defect: 1 piece of foreign matter = 1 full defect
Foreign matter includes all organic and inorganic non-coffee material found in green coffee bags, such as: sticks, glass, stones, nails, wire, etc., which represent a health hazard and give the green beans a bad appearance. The presence of non-coffee material is a clear sign of poor processing and grading. Foreign matter can seriously damage equipment, specifically grinders.
Cup: Contamination from foreign matter represents a health hazard and can affect the green coffee, causing various off-flavors.
Consideration: Affects appearance of the green coffee and can cause damage to roasting and grinding equipment.
Cause(s): Various: Foreign matter can be accumulated at any step in the process.
Remedies: PROCESSING:Foreign matter can be removed and/or avoided by:
  • selective picking and with the use of a flotation tank;
  • (washed process) maintaining cleanness in the wet mill, drying patios and work clothing; and
  • using proper equipment such as de-stoners, catadoras, bean sorters, gravity tables and magnets to remove foreign matter.