tags: [] - coffee/green-beans - coffee/green-beans/grading - coffee/quality aliases: - Coffee defects - Green bean defects - Coffee grading defects

Green Coffee Defects¶

Tags: #coffee/green-beans #coffee/green-beans/grading #coffee/quality Aliases: Coffee defects, Green bean defects, Coffee grading defects Related: Green Coffee Grading | Green Coffee Grading Methods | Quality Control MOC | Coffee Processing Methods MOC Status: ✅ Complete

Overview¶

Green coffee defects are physical flaws in unroasted beans classified by severity into two categories: Category 1 (primary) defects, which have serious cup impact and each count as one full defect, and Category 2 (secondary) defects, which are less severe and require multiple beans to equal one full defect. Defects are counted in a standard 350 g sample and the total used to determine the lot's grade, as part of the SCA and origin-specific grading systems detailed in Green Coffee Grading.

Category 1 Defects (Primary / Full Defects)¶

Defect	Cause	Appearance	Cup Impact	Defect Value
Full Black	Bean died on tree or ground before harvest	Completely black throughout	Sour, fermented, unpleasant	1 bean = 1 full defect
Full Sour	Severe over-fermentation	Brownish, opaque, vinegar smell	Vinegary, acetic, harsh	1 bean = 1 full defect
Dried Cherry (in washed coffee)	Unpulped cherry in washed lot	Whole dried cherry or bean with dried fruit attached	Inconsistent, fruity defect notes	1 cherry = 1 full defect
Severe Insect Damage	Coffee borer beetle, 3+ holes	Extensive damage, multiple holes	Off-flavours, fermentation	2–5 beans = 1 full defect
Foreign Matter	Contamination during processing or handling	Stones, sticks, metal, plastic, glass	No direct flavour impact but indicates poor QC	1 piece = 1 full defect
Fungus/Mould	Excess moisture during storage or processing	White, grey, or coloured fuzzy growth	Musty, mouldy, contaminated	1 bean = 1 full defect

Category 2 Defects (Secondary / Partial Defects)¶

Defect	Cause	Appearance	Cup Impact	Defect Value
Partial Black	Partial bean death or damage	Partially black (¼ to ¾ of bean)	Milder than full black, still negative	2–3 beans = 1 full defect
Partial Sour	Localised over-fermentation	Partial brown discolouration	Milder sour notes	2–3 beans = 1 full defect
Parchment	Hull not fully removed during milling	Silvery or golden papery hull still attached	Minimal flavour impact; indicates poor processing	2–5 beans = 1 full defect
Floater	Low density — immature, insect damage, or poor drying	Light weight, pale colour	Underdeveloped flavour, grassy	5 beans = 1 full defect
Immature/Quaker	Picked before full ripeness	Pale, chalky, light weight; stays pale when roasted	Peanutty, grassy, astringent	5 beans = 1 full defect
Withered	Water stress during growing	Wrinkled, shrivelled	Weak, underdeveloped	5 beans = 1 full defect
Shell (Elephant Ear)	Malformed bean development	Hollow, shell-like, deformed	Roasts unevenly, weak flavour	5 beans = 1 full defect
Broken/Cut/Chipped	Mechanical damage during processing	Physically broken pieces	Roasts too quickly, creates inconsistency	5 beans = 1 full defect
Hull/Husk	Outer hull fragments not removed	Brown, papery pieces	Chaffy; can burn during roasting	2–5 pieces = 1 full defect
Slight Insect Damage	Coffee borer beetle, 1–2 holes	Small holes, minor damage	Minimal if limited	2–5 beans = 1 full defect

Calculating Defect Scores¶

The SCA standard method uses a 350 g sample spread on a white grading surface and hand-sorted. Each defect identified is categorised as Category 1 or Category 2 and the appropriate equivalents applied. The totals are summed to give a final full-defect count.

Example calculation:

1 full black bean = 1.0 full defect
3 partial black beans = 1.0 full defect (3:1 ratio)
5 quakers = 1.0 full defect
10 broken beans = 2.0 full defects
Total: 5.0 full defects

Most specialty standards permit a maximum of 5 full defects per 350 g for top grades. See Green Coffee Regional Grades for country-specific thresholds.

Key Facts¶

Category 1 (primary) defects count as 1 full defect per bean or piece; Category 2 (secondary) defects require 2–5 beans to equal 1 full defect
Standard sample size is 350 g; defects are hand-sorted on a white surface
The most severe defects — full black, full sour, mould — have immediate and significant cup impact
Most specialty programmes use a maximum of 5 full defects per 350 g as the threshold for Grade 1
Defect classification systems vary by origin; the SCA framework is the most widely used international standard

References¶

Changelog¶

Date	Change
2026-05-03	Compliance review: added frontmatter, metadata block, all required sections; fixed table alignment; fixed path-prefixed wikilink in Related MOCs; replaced non-coffee tags

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