Quality Metric
Screen Size
A measurement of coffee bean size using numbered screens. Each number represents 1/64 inch diameter. Specialty coffee typically runs 15-18. Size affects roast uniformity more than cup quality.
Definition
What screen size measures
Screen size is determined by passing green coffee through screens with progressively sized round holes. Each screen number represents 1/64 inch. Screen 17 = 17/64 inch = approximately 6.75mm.
Coffee is graded by the screen it doesn't pass through. "Screen 17/18" means beans that stayed on screens 17 or 18 but fell through 19. Size grading creates more uniform lots for consistent roasting.
Common screen sizes
Why Roasters Care
What screen size means for roasting
Roast uniformity
Consistent bean size means consistent heat absorption. Mixed sizes roast unevenly--smalls scorch while larges underdevelop.
Not a quality proxy
Bigger isn't better. Ethiopian beans tend smaller than Central American but cup equally well. Size is variety and origin dependent.
Blend matching
When blending, match screen sizes. A screen 18 Brazil with screen 15 Ethiopia creates roast challenges.
Our Approach
How we use screen size
Include on spec sheets
Every lot includes screen size distribution. You'll know what you're getting before roasting.
Ethiopian context
Ethiopian beans run smaller than many origins. Don't expect screen 18. Screen 15-17 is standard for quality Ethiopian.
Uniformity over size
We prefer consistent size distribution over large beans. A tight 15-16 grades better than scattered 14-18.
Blend recommendations
Ask us for blend advice. We'll match screen sizes across components for even roasts.
Current Inventory
Coffees with screen size data
WUSH WUSH
Oromia, Hambela
Sangaria | Fruit Bomb | Floral | Sweet Finish
Natural, 120 hours dry Fermentation! · In Stock
Natural ARDI
Sidama, Damo
Clean Strawberry | Peach | Sweet Finish
Natural · In Stock
Harrar Gr 1
Oromia, Micheta
Chocolate | Barries | Carmel | Full Body
Natural · In Stock
Washed GUJI
Oromia, Bensa
Black Tea | Floral | Bergamot
Fully washed · In Stock
NATURAL SIDAMA GR 4
Sidama
Dark Chocolate | Nuts | Medium Acidity | Complex | Comforting
Natural · In Stock
Natural Sidama American Decaf
Oromia, Sama
Crisp Apple | Toasted Almond
UVVW · In Stock
Deep Dive
Density & Screen Size: What They Tell You
How bean density and screen-size distribution predict roast behavior, cup sweetness, and lot uniformity.
Related Terms
More Quality Metrics
Water Activity (aW)
Measure of free moisture. Below 0.60 is stable; above 0.65 risks mold.
Moisture Content
Percentage of water in green coffee. Target 10-12% for stability.
Density
Bean mass per volume. Affects heat transfer and roast development.
Q Score
Cupping score from a certified Q-grader. 80+ is specialty grade.
Q Grader
Licensed coffee professional certified by CQI to evaluate specialty coffee.
Defects
Physical or sensory flaws that reduce coffee quality and grade.
Want complete spec sheets?
We provide screen size, moisture, water activity, and cupping scores on every lot.