Coffee is labeled as specialty and judged by two ratings - a bean grade and cupping rating. When it comes to the bean grade, the coffee is divided into different categories when being processed. The judgment criteria are defects, ripeness, size, and moisture content.
Once you have sorted the best coffee beans, a sample batch is then roasted and tasted in a cupping process. The coffee roaster then rates it by flavor, sweetness, balance, aftertaste, body, and acidity.
According to these factors, the coffee rated above 80 on an SCA 80 to 100 scale is considered a specialty coffee. This is the best coffee available, usually grown on a single farm or estate.
Coffee that scored 80-85 is considered very good, coffee that scored 85-89 is excellent and the coffee with the rating of 90-100 is considered outstanding.
The grades above 90 aren’t that common though and are considered a luxury or premium coffees with considerable distinction, such as Gesha.
The coffee has been rated according to this system only recently, first used in 1974 and associated with the third wave of coffee. Before that, most coffees were lower in quality, what we would consider being commercial grade today.
Hope that helps!