Color Sorting Coffee Beans
Color sorting is frequently used to remove the defective coffee beans that were not removed during coffee processing or hulling. Many countries sort coffee beans by hand due to inexpensive labor, but for most countries investment in a color sorting machine, or color separator, is necessary. There are several types of color sorting instruments available on the market produced by two companies: Sortex and Xeltron.
The Color Sorter
The methodology behind color sorting machines is similar. The color of each coffee bean is quickly measured using a type of CCD camera system and depending on this wavelength measurement the bean is either allowed to flow downward or is shot with a puff of air into the reject pile. Monochromatic machines remove white and black coffee beans since they have a lighter or darker hue than the average. The more specific bichromatic color sorting machines detect and eliminate coffee beans that are white, unripe, broken, insect damaged, and black.