Introduction
Table of Contents
The SCA Green Coffee Classification Standard is one of the best methods for grading coffee beans. It is considered superior to some national systems (such as the screen-size-based grading system used in East African countries like Kenya) because it establishes a clear relationship between bean defects and cup quality. However, to apply it effectively, you need to understand the basic types of defects that can occur in green coffee.
Even with careful selection, grading alone does not determine coffee quality—it simply helps identify and eliminate factors that negatively affect it.
This article explains the key defect concepts found in green coffee classification systems, including how to identify them, how they influence flavor, and how to manage them during processing.
Specialty Coffee Grading Standards
Specialty coffee is classified based on visual inspection and cupping evaluation after roasting.
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Visual inspection involves taking a 300-gram sample of green coffee and counting all defective beans and foreign materials (referred to as “full defects”).
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To qualify as specialty coffee, a sample must have zero primary defects and fewer than five secondary defects.
Thus, defect grading is one of the key determinants of whether a coffee can be classified as Specialty Coffee.
Although many producers rarely focus on these details, they are crucial for those pursuing SCA certification or working professionally in coffee grading and quality control. For deeper study, you can consult the SCA Arabica Green Coffee Defect Handbook.
Understanding Primary, Secondary, and Full Defects
According to the SCA Coffee Beans Classification, defects are categorized as follows:
Primary Defects
Defect Name |
Translation |
Count Equivalent* |
|---|---|---|
| Full Black | Completely black bean | 1 |
| Full Sour | Fully sour bean | 1 |
| Pod/Cherry | Dried coffee cherry | 1 |
| Large Stones | Large stones | 2 |
| Medium Stones | Medium stones | 5 |
| Large Sticks | Large sticks | 2 |
| Medium Sticks | Medium sticks | 5 |
SCA states that a Specialty Coffee sample may contain no more than five full defects per 300 grams—and no primary defects at all.
Secondary Defects
Defect Name |
Translation |
Count Equivalent* |
|---|---|---|
| Parchment | Bean with parchment | 2–3 |
| Hull/Husk | Husk fragments | 2–3 |
| Broken/Chipped | Broken bean | 5 |
| Insect Damage | Insect-damaged bean | 2–5 |
| Partial Black | Partially black bean | 2–3 |
| Partial Sour | Partially sour bean | 2–3 |
| Floater | Lightweight bean | 5 |
| Shell | “Elephant ear” bean | 5 |
| Small Stones | Small stones | 1 |
| Small Sticks | Small sticks | 1 |
| Water Damage | Water-stained bean | 2–5 |
The “Count Equivalent” indicates how many occurrences of each defect type equal one full defect (a complete defect unit).
Definition Summary
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Primary Defects: Major flaws or foreign materials that have a severe negative impact on cup quality and are easy to identify.
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Secondary Defects: Lesser flaws that mildly affect flavor and are harder to detect.
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Full Defects: The combined total of both primary and secondary defects, representing the overall defect level of a coffee sample.