Most coffee regions use grading terms to indicate size. Most grade variables do not assess bean ripeness at picking or other taste related qualities.
No matter which method is used to extract the coffee beans from the cherries, once they have been freed from their encasing layers, they are sent through a mill that removes as much of the remaining silverskin as possible.
Because they have not been roasted, their color is a cloudy yellowish beige.
Bean size distribution is carried out by means of perforated pates commonly called screens. Depending on the shape of the holes screens can be grouped in two categories: rounded and slotted.
Typically the size of beans is expressed on a scale of 10 to 20.
Bean size plays an important role for roasted whole coffee beans because many consumers associate bean size to quality; however, larger beans do not necessarily taste better than smaller.
Next they are graded by weight. Beans are sorted by using an air jet to separate heavy and light beans.
Then, the beans travel along a conveyor belt, where workers with eagle eyes remove anything that doesn’t belong, including broken beans of the wrong size, the defects, black beans and any pebbles that have sneaked in.
Grading by color can be accomplished by hand picking, electronically with monochromatic light to sort out the black beans, biochromatically to eliminate brown and bleached beans or flourimetrically to eliminate ‘sinker’ beans.
When the sorting process is complete, the beans are bagged in burlap sacks that are colorful marked with country of origin and the logo of the supplier.
Many factors must be considered in grading coffee beans. These include the region, altitude, care during cultivation, type of harvesting and accuracy in production.
Although coffee is produced throughout Brazil, the highest grade beans known as Brazilian Santos or Bourbon Santos – come from the Sao Paulo region.
Sorting and grading of coffee beans
