Screen size in short: screen size measures green coffee beans by the holes they will not pass through, in 64ths of an inch. A screen 14 bean is about 14/64 inch, or 5.6 mm, wide. Ethiopian heirloom coffees tend to be small to medium, and many specialty Ethiopian lots fall around screen 14 to 16. In Ethiopia, screen size is not part of the official Grade 1 to 5 system; grade is based on defects and cup quality.
What Is Coffee Screen Size?
After milling, green coffee is shaken over a stack of metal plates (screens) with round holes. Each screen has a number, and that number is the hole diameter in 64ths of an inch. Beans that stay on top of a screen are "that screen and up." A lot described as "screen 15+" means every bean was too large to fall through 15/64-inch holes.
Coffee Screen Size Chart
| Screen | Inches | Millimeters | Common description |
|---|---|---|---|
| 13 | 13/64 | 5.2 mm | Small |
| 14 | 14/64 | 5.6 mm | Small to medium |
| 15 | 15/64 | 6.0 mm | Medium |
| 16 | 16/64 | 6.4 mm | Medium to large |
| 17 | 17/64 | 6.7 mm | Large |
| 18 | 18/64 | 7.1 mm | Very large |
| 19 to 20 | 19/64 to 20/64 | 7.5 to 7.9 mm | Extra large |
Peaberries, where the cherry grew one round bean instead of two flat-sided ones, are sorted separately on slotted screens.
Ethiopian Coffee Screen Size vs Ethiopian Grade
This is where people get confused. Some origins name their grades after bean size: Kenya AA and Colombia Supremo are large-screen grades. Ethiopia does not work that way.
- Ethiopian grade (Grade 1 to 5): based on physical defects in a 300-gram sample and on cup quality. See Ethiopian coffee grades explained.
- Screen size: a separate physical spec that exporters and buyers agree on, such as "Grade 1, screen 14+."
So a Grade 1 Ethiopian coffee can be small-screen and still be top quality. Bigger is not automatically better.
Why Ethiopian Heirloom Beans Run Small
Most Ethiopian coffee comes from thousands of local heirloom varieties, many of them small-beaned, grown at high altitude where cherries mature slowly. Small, dense beans are often some of the most flavorful in Ethiopia. Some specialty roasters even buy screen 14 lots on purpose because the smaller beans can taste sweeter and more focused. Harrar is the exception that is traditionally sorted by shape, into Longberry, Shortberry and Mocha. See our Harrar coffee guide.
Why Screen Size Matters for Roasting
- Even roasting: beans of similar size absorb heat at the same rate. A lot with mixed sizes can roast unevenly, with small beans running dark while big beans stay underdeveloped.
- Roast planning: smaller, dense Ethiopian beans can take heat well but can also scorch if the charge temperature is too high.
- Consistency: a tight screen spec helps a roaster repeat the same profile batch after batch.
- Price: larger, uniform screens can cost more, but they do not guarantee a better cup.
What to Ask When Buying Ethiopian Green Coffee
When you buy Ethiopian green coffee, ask for the grade, the processing method, the screen size spec, the crop year and a cupping sample. Our Ethiopian green coffee wholesale guide covers the full checklist.
Buna Utopia sells Grade 1 Ethiopian green coffee for home roasters and wholesale buyers. Ask us for the screen size and full specs of any current lot through the wholesale page, or shop green beans here.
Frequently Asked Questions
What does screen 14 mean in coffee?
The beans did not pass through a screen with 14/64-inch (about 5.6 mm) holes. It is a small to medium bean size, common for Ethiopian heirloom coffee.
What screen size is Ethiopian coffee?
Many specialty Ethiopian lots fall around screen 14 to 16, but it varies by region, variety and how the exporter sorts the lot.
Is a bigger screen size better?
Not necessarily. Uniform size helps roasting, but flavor depends on variety, altitude, processing and defects. Many excellent Ethiopian coffees are small-screen.
Is screen size part of Ethiopian Grade 1?
No. Ethiopian grades are based on defect count and cup quality. Screen size is a separate spec.
How many millimeters is screen 15?
About 6.0 mm (15/64 of an inch).
Written by Alula Kassa, founder of Buna Utopia, a direct-trade Ethiopian coffee importer based in Detroit, Michigan. Read more about Alula.
