Imagine you’re scrolling through a coffee importer’s offer list. And while scanning through the details of a coffee, you find the column Coffee Grades. Depending on the coffee’s origin, you’ll see grade-1 or Brazil NY 2/3 in the grades column. But what are coffee grades, and what do they tell you?
In this blog, we’ll give you a basic understanding of coffee grades.
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.
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 cup quality.
The world of coffee lacks a universal coffee grading system, but luckily, there are three elements you can use to speak the same language with your coffee importer.
Most coffee sellers grade, or classify, coffees through;
In other words: by seeing, measuring size, and tasting, we pinpoint the level of quality.
Through the defect count and the screen size of the beans, we conduct a visual inspection of the coffee. We look at bean uniformity, cleanliness, and the presence of defects through a process called green grading.
And with cupping, we perform a sensorial-analysis of each coffee. By using quality protocols, like the SCA cupping protocol, we cup and assess a coffee on balance, uniformity, cleanliness, sweetness, body, acidity, fragrance/aroma, and flavor.
Both defect count, screen size, and the sensorial-analysis should match with the contract between you, the buyer, and the seller – often a coffee importer or exporter. Let’s start with the influence of coffee defects on coffee grades.
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.
All these events cause coffee to defect and will eventually harm the cup quality, and in some cases can even influence the safety for human consumption. The count of these defects weighs heavily on the outcome of the coffee grade. The fewer the defects, the higher the grade. One of the prime systems for recognizing, labeling, and categorizing defects is the SCA Green Arabica Classification System, or short, GACCS.
The GACCS distinguishes primary and secondary defects.
Full black, full sour, or severe insect damage are all examples of primary defects. A primary/ full defect has an enormous effect on cup quality. Secondary defects do not harm the coffee’s taste like the primary defects do. This is why many green grading systems have an ‘equivalency system’, where you need a certain number of defective beans to count as 1 defect count. The more effect the defect has on the cup quality, the heavier the weight of the defect is. If the effect is smaller, less weight is given. For example, you only need 1 fully black bean to count as 1 defect. But you need 10 beans with slight insect damage to count as 1 defect.
Don’t be alarmed. If you solely focus on specialty coffee, you usually won’t find primary defects in your coffee. And the GACCS only allows 5-secondary defects within a batch of specialty coffee. Learn more about the SCA’s GACCS here.
But again, take note that the count of defects, as well as the types of defects, can differ per origin. And not all coffees that are considered specialty coffee have only 5 secondary defects. If the grade is unclear, reach out to your coffee importer to receive more information on the grading standards of the particular coffee.
It takes time to develop a keen eye for spotting coffee defects. To give you a head start, you can find the Specialty Grading Specification table underneath. And you can download our coffee defect poster to start visually recognizing green coffee defects.
Now let’s move on to screen 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.
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.
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.
So, don’t be fooled by the size. Cup and judge.
The second reason why screen size takes an important role within coffee grades is roast uniformity. Simply put: if you roast a batch containing all the shapes and bean sizes on the market, you’ll get an inconsistent batch of coffee. Because heat application isn’t uniform when roasting uneven beans. Some beans will over-roast, others stay underdeveloped.
Sorted beans, categorized by screen size, empower you as a roaster to transfer heat uniformly. As a rule of thumb, 95% of a specialty coffee batch should fall into the screen size of your contract. Even after coffee exporters screen the coffees in large volumes, we re-screen a 300-gram pre-shipment sample with small sieves and check if 95% stays in the correct screen.
So far we’ve covered how coffee defects and screen sizes define coffee grades. Two technical methods that influence the grade. Sensorial analysis, a.k.a. cupping, is the third element that enables you to ‘talk’ the same language with your coffee importer. A cupping protocol, recognized by both you and your importer, helps to guide and/or streamline the conversation about the quality of the coffee.
The most common cupping protocol within the specialty coffee market is the SCA cupping protocol. Through this protocol, you assess the balance, sweetness, body, acidity, fragrance/aroma, and flavor of a coffee sample, as well as if the coffee has any taint or fault issues, meaning it is not uniform or fully clean.
The final score, the sum up of all points on the numeric scale, gives you an idea of the quality.
The purpose of this cupping protocol is the determination of the cupper’s perception of quality. The quality of specific flavor attributes is analyzed, and then drawing on the cupper’s previous experience, samples are rated on a numeric scale.
To summarize: grades function as a compass. They help you to navigate within a coffee importer’s offer list as you explore new coffees for your menu.
In the International Coffee Organization’s 2018 National Quality Standards you can find information on various grading systems of different countries, as well as information on what national bodies are governing these grading standards.
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