All coffee lovers know that not all coffee is created equal. Some coffee beans, usually the more expensive sort, is like heaven in a cup while other coffee beans make you wonder why anyone would enjoy them. There is a way, or rather multiple ways, you can learn what quality coffee beans are.
Grading involves assessing various factors, ranging from the altitude and region where the beans are grown to the size, shape, and color of the beans. Unfortunately, it’s not as straightforward as some people want to make you believe. The problem: There is no universal grading system for premium-grade coffee beans or standard-grade coffee beans.
While the Specialty Coffee Association (SCA) sets some global standards for specialty coffee beans, and the European Union (EU) also has its own definitions for commercial coffee beans grades, this doesn’t change the fact that each coffee-producing country has its own system to grade coffee beans.
In this article, we will try to clarify this complex topic in a comprehensive form. In particular, we look at the important factors of how to grade coffee beans, the common criteria, and the methods used to assess coffee beans.
What Is Coffee Grading?
Coffee bean grading is a systematic evaluation of coffee beans to determine their quality and suitability for consumption. This process is important for maintaining consistency in flavor, aroma, and overall quality of coffee beans. Grading specialty coffee beans includes a combination of subjective and objective assessments (not everyone will have the same opinion during a cupping session).
Let’s take a look at the factors contributing to the final grade of coffee beans.
Common Criteria Used To Grade Coffee
Altitude and Region
As you may know, altitude and region play a significant role in determining a coffee bean’s flavor profile. Both are also important for grading coffee. In general, coffees grown at higher altitudes are often considered superior with more nuanced and complex flavors. Different regions also impart distinct characteristics to the coffee, influenced by factors like soil composition and climate.
Botanical Variety
Coffee plants belong to different botanical varieties. You’re likely familiar with the two most famous ones: Arabica and Robusta. Arabica beans are generally considered superior in flavor and quality. The botanical type is a key criterion in grading. It influences the final grade and market value.
Processing Method
The processing method used for processing coffee beans also impacts the final quality. The two main processing methods are the wet process and the dry process, though other processing methods are also starting to become more popular. The processing method influences a bean’s flavor, acidity, and overall profile, contributing to its grade.
Bean Size, Shape, or Color
If you buy ground coffee, you won’t get to see any of the physical attributes of coffee beans, including size, shape, and color. However, these factors are as important for the grading process as other aspects.
Number of Defects
Defects in coffee beans can happen during cultivation, processing, or transportation. As you may guess, defects have a negative impact on the final grading score. Graders assess the number of defects in a sample. These defects range from insect damage to mold or other imperfections like chipped beans.
Roast Appearance and Cup Quality
Now, here’s one of the more subjective aspects of grading: The roast appearance and cup quality. The roast level influences the flavor profile, with light roasts preserving more of the bean's inherent characteristics, while dark roasts introduce smokiness and bitterness. Cupping (see below) is used to evaluate the coffee's aroma, flavor, acidity, body, and overall “cleanliness”.
Bean Density
The density of coffee beans measures their compactness and is influenced by factors like altitude, climate, and bean maturation. Denser beans are often considered higher quality, as they tend to have more pronounced and well-developed flavors.
Is There A Universal Coffee Grading System?
There are internationally recognized standards for grading, yes, but there is no universal system that is used everywhere. Finding the best coffee beans can be a challenge because of that.
Different countries or regions have their own grading systems based on unique criteria that reflect local preferences and industry practices. This lack of standardization can be confusing because a grade AA coffee from Tanzania isn’t the same as a grade AA coffee from Yemen, for example.
That’s why it’s important that coffee producers and buyers are familiar with the specific grading systems relevant to their beans.
3 Simple Ways Green Beans Are Graded
Defect Count
One of the primary methods for grading green coffee beans is the defect count. Graders inspect a sample for various defects. The lower the defect count, the higher the grade of the coffee.
The Screen Size
Another common method is grading based on screen size. Coffee beans are sorted through screens with specific hole sizes. Larger beans pass through larger screens, while smaller beans are retained.
Tasting The Coffee or Cupping Coffee
Cupping is a vital step in the grading process. Professional tasters, known as cuppers, evaluate the coffee's aroma, flavor, acidity, body, and overall cleanliness. Cupping is a systematic assessment of the coffee's sensory attributes and is an essential tool for determining a coffee’s final grade.
What Are Coffee Defects?
Coffee defects can negatively impact the flavor, aroma, and overall quality of the coffee. The highest grade specialty grade coffee beans must be free from faults.
Common defects are:
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Insect Damage
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Mold or Fungus
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Chipped or Broken Beans
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Unripe or Overripe Beans
Primary And Secondary Defects
Coffee defects are categorized into primary and secondary defects.
Primary defects have a more significant impact on the quality of the coffee and include major issues like insect damage or mold.
Secondary defects are considered less severe and include minor imperfections like small chips or slight discoloration.
How To Recognize Coffee Defects?
Recognizing defective coffee beans requires a keen eye and experience in grading. Graders carefully inspect samples and check for visual cues (discoloration, irregularities in shape, or the presence of foreign matter).
Cupping also plays a role in identifying defective beans because professional cuppers can detect off-flavors or unusual characteristics in the coffee.
What Is The Screen Size Of Coffee?
As mentioned above, grading includes sorting beans by their screen size. During this process, the beans are filtered through screens with specific hole sizes.
The specified screen size used in this process can vary. Screen size is measured in 64ths of an inch. For example, a size 16 bean is 16/64ths of an inch in diameter, while a size 18 is slightly larger at 18/64ths. Large beans are often seen as higher quality.
This method ensures uniformity in size within each grade. This contributes to a consistent roast and flavor profile. It’s important to note that Ethiopia doesn’t put a big emphasis on screen size in its grading system.
How Does the Size Of The Coffee Bean Affect Roasting?
The size of coffee beans impacts the roasting process and the final flavor of coffees.
On one hand, larger beans tend to need more time to absorb heat during roasting. This extended roasting time allows for the development of more complex flavors.
On the other hand, smaller beans roast more quickly and may exhibit brighter acidity and a different flavor profile.
What Is Cupping Coffee?
Cupping is a standardized tasting process. The coffee industry uses cupping to judge the sensory attributes of coffee. Professional tasters assess the aroma, acidity, body, or aroma and whether the cup is free of cup faults and taints.
While professional cupping is probably nothing you’ll get involved in as an end consumer, there are places that offer cupping sessions to visitors. It’s an interesting experience you should try if you have the chance. You'll learn how to compare coffee beans, get more insights into coffee grades, and learn how to assess the overall cup quality.
Exploring Coffee Grading Systems By Region
As already mentioned, grading systems can vary significantly from one region to another. This depends on local preferences, traditions, and industry standards.
As you can see on our grading chart, many countries have unique grading systems that prioritize different criteria. A good example of this is Ethiopia which doesn’t care much about screen size and more about the quality.
You can also see that some countries do not include elevation in their grading - which is mainly due to the fact that some regions grow coffee in more or less the same elevation, while countries like Nicaragua grow coffee anywhere from 500 to 1200 masl.
Final Thoughts
We could write much more about various aspects of grading as this is a complex and fascinating process, but hopefully, this article has given you a basic understanding of what goes into coffee grades. Specialty coffee is another story, and you may want to read our article just about specialty-grade coffee beans.
In summary, coffee grading determines the quality of green coffee beans. Aspects like altitude and region, the size, shape, and color of the beans, defects, and cup quality (aroma, flavor, body, etc.) all play their role in what grade a coffee receives. However, there is no universal coffee grading system, and different coffee-growing regions place greater importance on some aspects than others.
