Green Coffee Classification and Grading
i) Speciality Coffee Association of America (SCAA) Green Coffee Classification
The green coffee classification standard provided by the SCAA is an excellent method to classify coffees. It is superior over some systems in that it better accounts for the relationship between defect and cup quality. However, it leaves out a few of the important defects that can occur in coffee (See the Brazilian Green Coffee Classification).
To classify a coffee, 300 grams of properly hulled coffee is classified according to the standards given below. 100 grams of this coffee is sorted using screens 14, 15, 16, 17, and 18. The coffee remaining in each screen is weighed and the percentage is recorded. Since classifying 300 grams of coffee is very time consuming, 100 grams of coffee is typically used. It is recommend that if the coffee is of high quality with few defects to use 300 grams. If the coffee is of a lower quality with many defects 100 grams will often suffice in a correct classification as either Below Standard Grade or Off Grade. The coffees then must be roasted and cupped to evaluate cup characteristics.
Speciality Grade (1): Not more than 5 full defects in 300 grams of coffee. No primary defects allowed. A maximum of 5% above or below screen size indicated is tolerated. Must possess at least one distinctive attribute in the body, flavour, aroma, or acidity. Must be free of faults and taints. No quakers are permitted. Moisture content is between 9-13%.
Premium Grade (2): No more than 8 full defects in 300 grams. Primary defects are permitted. A maximum of 5% above or below screen size indicated is tolerated. Must possess at least one distinctive attribute in the body, flavour, aroma, or acidity. Must be free of faults and may contain only 3 quakers. Moisture content is between 9-13%.
Exchange Grade (3): 9-23 full defects in 300 grams. Must have 50% by weight above screen size 15 with no more than 5% of screen size below 14. No cup faults are permitted and a maximum of 5 quakers are allowed. Moisture content is between 9-13%.
Below Standard Grade (4): 24-86 defects in 300 grams.
Off Grade (5): More than 86 defects in 300 grams.