Does Jamaica Blue Mountain Coffee Have Grades? A Guide to Coffee Bean Classification Systems

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FrontStreet Coffee - Introduction to Coffee Grading Systems

1. Grading by Screen Size

Screen size grading is a method of classifying coffee beans by their size. Raw coffee beans pass through iron screens with holes to determine their size and thus their grade. The hole size in the screens is measured in units of 1/64 inch (less than 0.4mm), so the screen number indicates how many 1/64 inches it represents. For example, a size 17 screen has holes measuring 17/64 inches, approximately 6.75mm. The larger the screen number, the larger the coffee beans.

2. Grading by Altitude

This grading standard is mainly based on the fact that coffee produced at higher altitudes generally has better quality than coffee from lower altitudes. Because higher altitudes have lower temperatures, coffee development is slower, which facilitates the accumulation of desirable compounds. Additionally, mature beans expand well during roasting, which is beneficial for the roasting process and results in more consistent quality. These coffee beans have high density and relatively hard texture, producing more complex flavors after roasting, which is why this method is sometimes referred to as grading by "hardness."

3. Defect Bean Grading

Many coffee-producing countries primarily use manual harvesting, but often employ dry processing methods. Dry processing can easily mix in underdeveloped beans and other defects, so grading is based on defect counts. The evaluation method involves randomly sampling 300 grams and placing them on black paper, as black paper best avoids glare. Professional graders then screen and identify defective beans in the sample, accumulating different scores based on the number and type of defects. Coffee-producing countries using this grading standard include Ethiopia and Peru.

Jamaica uses a comprehensive rating standard that considers region, altitude, screen size, and defect bean percentage, with the defect bean percentage serving as an important basis. Jamaica strictly controls the proportion of defective beans, with the maximum defect rate in any grade not exceeding 4%.

Jamaican Blue Mountain coffee is graded according to different altitudes where different grades of coffee are produced. Authentic Blue Mountain coffee must be made from beans grown between 910-1700m altitude. Coffee grown at 460-910m is called Jamaican High Mountain coffee, while coffee grown below 460m is called Jamaican Prime coffee. Like wine, Blue Mountain coffee has different estates to distinguish growing regions, with three main regions: St. Andrew, Portland, and St. Thomas.

Pure Blue Mountain coffee has four grades: NO.1, NO.2, NO.3, and PB (Peaberry). It is traditionally packaged in 70kg wooden barrels and comes with a quality certification issued by the Coffee Industry Board of Jamaica (CIB). Due to limited production and Japan's investment in Jamaica's coffee industry, which grants them priority purchasing rights, only 10% of the Blue Mountain supply is available to other countries after Japan purchases 90%. This creates a perpetual shortage in the international market, driving up prices. Authentic Blue Mountain coffee cannot be found in supermarkets. So-called "Blue Mountain blend" is made by mixing other coffee varieties with high mountain coffee or very small amounts of Blue Mountain coffee, which is far inferior to 100% Blue Mountain.

Knowledge Bonus

Only more meticulous cultivation can yield higher quality coffee, and only high-quality coffee can receive high ratings. Therefore, detailed segmentation and strict control of coffee grading are certainly beneficial and without harm to improving coffee quality.

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