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

FrontStreet Coffee - Introduction to Coffee Grading Systems

1. Grading by Screen Size

Screen-size grading classifies coffee beans by their dimensions. Green beans pass through iron screens with punched holes; the holes they fit (or don't) determine the grade. Hole sizes are measured in units of 1/64 inch (less than 0.4mm), so the screen number tells you how many 1/64ths of an inch it represents — a size 17 screen has holes of 17/64 inches, roughly 6.75mm. The larger the screen number, the larger the beans.

2. Grading by Altitude

This standard rests on the observation that coffee grown at higher altitudes generally outperforms coffee from lower ones. Higher means cooler; cooler means the coffee develops more slowly, which favors the accumulation of desirable compounds. Denser, harder beans also expand well during roasting, which benefits the roast and produces more consistent quality — and the more complex flavors that follow. That density-and-hardness link is why this method is sometimes called grading by "hardness."

3. Defect Bean Grading

Many producing countries rely on manual harvesting but often process coffee by the dry method, which easily sweeps in underdeveloped beans and other defects — so grading is based on defect counts. The evaluation works like this: a random 300-gram sample is spread on black paper (black best avoids glare), and professional graders pick through it, identifying defective beans and accumulating scores based on the number and type of defects. Ethiopia and Peru are among the countries using this standard.

Jamaica takes a comprehensive approach, weighing region, altitude, screen size, and defect percentage together — with defect count as the decisive basis. Jamaica polices defects strictly: in any grade, the maximum defect rate may not exceed 4%.

Jamaican Blue Mountain is graded by the altitude at which each grade is grown. Authentic Blue Mountain coffee must come from beans grown between 910-1700m. Coffee from 460-910m is called Jamaican High Mountain, and coffee from below 460m is called Jamaican Prime. Like wine, Blue Mountain distinguishes its growing regions by estate, with three main ones: St. Andrew, Portland, and St. Thomas.

Pure Blue Mountain comes in four grades: NO.1, NO.2, NO.3, and PB (Peaberry). It is traditionally packed in 70kg wooden barrels and ships with a quality certification from the Coffee Industry Board of Jamaica (CIB). Production is limited, and Japan's deep investment in Jamaica's coffee industry secures priority purchasing rights — after Japan buys 90%, only 10% of the Blue Mountain supply is left for everyone else, which keeps the international market permanently short and prices high. You will not find authentic Blue Mountain on supermarket shelves, either. So-called "Blue Mountain blend" mixes other coffees with High Mountain beans or only traces of true Blue Mountain — a far cry from 100% Blue Mountain.

Knowledge Bonus

Only meticulous cultivation yields higher-quality coffee, and only high-quality coffee earns high ratings. Detailed segmentation and strict grading control are therefore unambiguously good for coffee quality.

FrontStreet Coffee Recommendation

Put this grading knowledge to work with FrontStreet Coffee's Jamaica Blue Mountain No. 1 — the top grade in the Blue Mountain hierarchy, from the historic Clifton Estate that has grown coffee since around 1750. The growing zones sit at an average of 4300 feet (1310.64 meters), and FrontStreet Coffee supplies complete origin certification plus the traditional wooden shipping barrels (15, 45, and 70 kg sizes) that have always marked genuine Blue Mountain — exactly the kind of documentation and provenance this article says to look for.

Roasted medium-dark and shipped within 5 days of roasting, it shows the classic Blue Mountain triad — sweetness, acidity, and bitterness in perfect accord — with dark chocolate, nuts, and cream caramel over a clean, gentle fruit-toned finish. For brewing, FrontStreet Coffee suggests a Kono dripper to accentuate that mellow body: 15g of coffee rested 4-7 days from roast date, ground a touch coarser than for light roasts (about the texture of white sugar), 87-88°C water, a 1:15 ratio, and three-stage pours of 30g bloom for 30 seconds, then to 120g, then to 225g.