How are Coffee Beans Graded?
Coffee beans are evaluated for quality based on different criteria, including defects, size, and cup quality. Different methods are used for this evaluation:
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The SCAA Green Coffee Classification Method is well-suited for specialty green coffee beans
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National Grading Standards for Green Coffee Beans: Each coffee-producing country has established its grading system for green coffee beans, reflecting regional preferences and standards.
The SCAA Green Coffee Classification Method
To effectively categorize coffee beans, starting with a batch of 300 grams of beans that have had their hulls removed is common. This batch is then passed through a series of screens, ranging from size 14 to 18. Each screen captures beans of a specific size. The beans left in each screen are then weighed, and each group's total batch percentage is calculated. Subsequently, the coffees must undergo roasting and cupping to assess their cup characteristics.
Specialty Grade Green Coffee
Specialty green coffee beans are defined by fewer than 5 complete defects per 300 grams, with no primary defects. They can deviate by up to 5% from the indicated screen size. Specialty coffee must exhibit at least one distinctive attribute in body, flavor, aroma, or acidity and must be free from faults, taints, and quakers. Moisture content ranges from 9% to 13%.
Premium Coffee Grade
Premium coffee beans should have no more than 8 full defects per 300 grams, with some leeway for primary defects. They can deviate up to 5% from the specified screen size. They must showcase at least one distinctive characteristic in terms of body, flavor, aroma, or acidity and must be fault-free with a maximum of 3 quakers. Moisture content should range between 9% and 13%.
Exchange Coffee Grade
Exchange coffee beans must have fewer than 23 full defects in a 300-gram sample. At least 50% of the beans by weight must be larger than screen size 15, with less than 5% falling below size 14. They should have no cupping faults and a maximum of 5 quakers. Moisture content should range between 9% and 13%.
Below Standard Coffee Grade
24 to 86 full defects per 300g
Off Grade Coffee
More than 86 defects in 300 grams
National Grading Standards for Green Coffee Beans
Before these beans make their way to roasters and into the aromatic brews enjoyed by millions, they undergo a critical evaluation process known as coffee grading. While many coffee professionals are familiar with the Specialty Coffee Association's (SCA) Green Coffee Grading Standards, a complex world of country-specific grading systems offers a unique insight into coffee's regional characteristics and quality measures.
Each coffee-producing country has developed its criteria for grading green coffee beans, often influenced by local agricultural practices, historical context, and market demands. These examples highlight the various methods used to grade coffee, primarily for the bulk coffee trade. They may not cover the specific details often used in niche and specialty markets.
Brazil
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Santos NY 2/3: Fine roast, Screen size 17/18.
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Santos NY 4/5: Good roast, Screen size 14/16
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MTGB: Indicates beans sized between Screen 15-16.
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SSFC: Coffee with clean, smooth, sweet flavors, medium acidity, and body, rated as Specialty grade (80+).
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NY: Reflects the quality standards of the Green Coffee Association of New York.
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COB: A classification from 1949 used mainly by Brazilian warehouses for grading.
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SSGC: Represents Arabica coffee with good quality, lightly astringent taste, low acidity, and body
Colombia
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Supremo: This high-grade washed Arabica coffee requires at least 95% of the beans to be screen size 17, with all beans above screen 14. It’s noted for its quality and size.
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Excelso: At least 95% of beans are of screen 14, with 50% reaching screen 15.
Central America
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SHB (Strictly Hard Bean): Grown at altitudes above 1350 meters, notably between 1,600 and 1,700 meters in regions like Huehuetenango, producing denser beans known for their full-bodied, acidic, and fragrant profile.
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HB (Hard Bean): Cultivated at lower altitudes between 1070 and 1200 meters, resulting in slightly less dense beans.
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EP (European Preparation): Focuses on meticulous hand sorting, requiring beans to be 100% above screen 15 and allowing a maximum of 8 defects per 300 grams, compared to the more lenient American Preparation standards.
Ethiopia
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Grade 1: Highest quality with small to medium-sized beans, 0-1 defects per 300g, and a bluish color.
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Grade 2: High quality, small to medium-sized beans, 4-8 defects per 300g, grayish color.
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Grade 3: Good quality, small to medium beans, 9-15 defects per 500g, greenish color.
Kenya
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PB (Peaberries): Single, round beans known for rich flavor.
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AA: Large beans through screens 17 and 18 (7.2 mm), highly prized for flavor.
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AB: Medium beans through screens 15 and 16 (6.6 mm), good quality.
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C: Smaller beans through screens 14 and 15.
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E (Elephant): Includes large "peaberries" and chipped beans called "Ears."
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TT: Lighter beans sifted from AA and AB by air.
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T: Smaller, lighter beans separated from grade C.
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UG (Ungraded): Beans that don't fit into specific grades.
Source: Green Coffee Beans Classification. www.coffeeresearch.org/