How Green Coffee is Graded.
Specialty coffee can be defined as beans that come from a specific climate in the world that are known for certain characteristics. But this is not the only way that the Specialty Coffee Association qualifies specialty coffee. It also has to be ethically sourced and sustainably farmed. This is usually the thing that is the hardest to judge as it requires eyes and ears on the ground.
Aside from climate of origin, whether the coffee is single origin or from multiple farms in one region within the microclimate, there is a way of determining the quality of cup that the coffee bean produces. This is what we know as coffee grade.
Coffee grades define the level of quality
A coffee grade is a quality classification. It tells you what quality classification the coffee has. A coffee grade helps sellers and buyers throughout the globe to align their expectations with each other.
Without taking a sip of coffee, you have a rough sense of the quality by looking at the grade within an offer list.
What are coffee defects, and how do they influence the grade?
Coffee beans are continuously at risk. While still dangling from a tree, insects can damage the seeds. You’ll see small black holes on the surface of the green processed beans. Or you can find broken and chipped beans damaged by processing machines in origin. And, even worse, you may find a full black bean that suffered water deprivation or overfermentation at the farm.
Is there a universal coffee grading system?
Although coffee grades give you a sense of quality, the grading systems throughout the world are fragmented. There is no universal grading and classification system, and every country governs its own system. Meaning, a grade 1 from Indonesia, may not be the same as a grade 1 from Peru. And an EP from Honduras may have a different defect count than an EP from Colombia.
Still, most of these fragmented grading systems rely on criteria like screen size, altitude or region, botanical variety, number of defects, processing, bean density, and the roast appearance and in the end taste in your cup.
Specialty Coffee Association Grading System
Coffee Grades by Size
Coffee beans come in all shapes and sizes. Within the coffee market, we’ve defined the size by measuring the beans against a rounded inch. 20/64 of an inch is the largest screen size, and 8/64 of an inch is the smallest. In this range, you’ll find all the acceptable screen sizes in coffee.
Before the seller bags the coffee, the beans are poured into large screens, or sieves, with round one-inch holes that separate the coffee by size. Gravity does the rest of the work. Because the large beans stay in the upper screens and the small beans tumble down until and end up in a smaller screen sized sieve.
After separating coffee by size, the beans are bagged per screen. But why is this important? There are two reasons.
Bigger beans, higher prices
Within the coffee market, the size of the beans matter. For one, several coffee origins define their premium prices by the size of the bean. For example, the price for the famous Kenya AA grade is higher than the smaller Kenya AB grade coffees. When the screen size is large, the price increases.
The main theory within the market is that high altitude coffees develop more slowly, have more density, and are larger in size than lower growing coffees. The latter, the statement on size, is a traditional take on quality. It’s not always accurate. Because small tasty Ethiopian coffee beans disprove this theory completely.
Coffee Grading in Ethiopia
The screen size of Ethiopian coffee is often small compared to other origins. Ethiopian coffees that grow between 1500 and 2000 m.a.s.l. or above, hover around screen size 14/64. However small, the beans develop slowly, have great density, and, if high in grade, taste extraordinary.
Coffee Grading in Africa and India
Except for Ethiopia, all African origins follow a lettered grading system. India also follows a similar grading method. These usually start with A or AA as the highest grade – which is normally for specialty coffee. Meanwhile, anything with a C grade and below is recognized as commercial coffee.
Outside of the list above, Kenya and Tanzania have a grade in between A and B (AB). In Kenya, instead of using a standalone B grade, they mix together the smallest A grade beans along with B grade beans.
While most coffee buyers would still prefer AA beans, AB beans can be just as good. In some cases, even better. ABs are usually the most abundant in a harvest and are used to represent other grades.
Other grades used in Kenya are E, TT, T, and MH/ML. E coffees, also known as the “Elephant” grade, are abnormally large beans. These form from a genetic defect where two seeds merge under one cherry.
TT beans are light-density E, AA, AB, and PB beans that don’t make the cut. T coffees are broken, faulty, or thin beans from the C grade.
MH/ML beans are usually the worst kind. They are cherries that fall on their own after ripening. Beans of this kind have an unpleasant and sour taste.
While grading can give you a good indicator of quality, the best way is by taste. Not everything can be determined by numbers and words on a website, grab a sample, make it in your preferred method (or try cupping!) and give it a go to figure out that you enjoy best.