Defect Counting and Green Grading

Defects are the physical faults in a green lot: beans damaged in the field, in fermentation, in drying or in handling, plus foreign matter. Counting them is how the trade turns "clean" into a number.

The counting convention

The widely used convention weights defects by how much damage they do. A full defect is one unit; several instances of a lesser fault together make one full defect.

Roughly, and depending on the standard applied:

Specialty grading conventionally counts defects in a 350 g sample of green coffee, with a common specialty threshold of no category 1 defects and a small number of full defects total. Commercial grades run considerably higher.

What each does to the cup

Not all defects matter equally, and it is worth knowing which ones you are actually paying to have removed.

• Full black — over-fermented or dead cherry. Produces heavy, dirty, fermented notes. Ruinous even in small numbers.
• Full sour — over-fermented or picked from the ground. Sharp, vinegary, unpleasant. Also ruinous.
• Insect damage — from coffee berry borer. Can carry mustiness and a hollow, papery flavour.
• Broken and chipped — roast unevenly and scorch, since the exposed surface takes heat faster.
• Floaters — low density, usually under-developed. Roast ahead of the batch and taste papery.
• Shells — malformed beans that fragment in the roaster and burn.
• Foreign matter — stones and sticks. A machine hazard rather than a flavour one, and a real one for a roaster's grinder.

The first two are why defect counts exist. A single full sour in a cupping bowl is detectable.

Sorting in India

Indian curing works run a sequence, and knowing it tells you where the count comes from.

1. Hulling and polishing — parchment or dried cherry removed.
2. Screening — separation by size.
3. Density separation — gravity tables remove floaters and lights.
4. Colour sorting — optical machines eject blacks, sours and discoloured beans.
5. Hand garbling — people at a belt removing what the machines left.

That last step is still normal practice in India and is genuinely effective at what optical sorters miss: shells, badly malformed beans and foreign matter. It is also labour that has to be paid for, and it is one of the real cost differences between an estate lot and a commodity one.

Ask whether a lot was hand-garbled after colour sorting. In a high-disease year this matters more than usual — see India's 2025/26 crop, where heavy monsoon rain raised black rot in arabica and fruit rot in robusta.

To which standard?

"Defect count 5" is meaningless without the standard. Ask:

• Which standard — the specialty convention, a national standard, or the exporter's own.
• Sample size — 300 g, 350 g, or something else.
• Full defects or bean count — a count of 12 beans is not a count of 12 full defects.
• Before or after the buyer's own hand-sort, if any.

Checking it yourself

This is the easiest arrival check in the trade and very few buyers do it.

Draw a representative sample, weigh out 350 g, spread it on a tray under good light, and pick through it. Twenty minutes per lot. Sort into categories, count, and compare with what you contracted.

Doing this once on every new supplier's first shipment tells you more about who you are dealing with than any amount of correspondence.

What to contract

Defect count not to exceed [n] full defects per 350 g, counted to the specialty convention, with zero category 1 defects; assessed on the pre-shipment sample and re-checkable on arrival.

Hoysala cures and grades its own coffee in Chikmagalur rather than through a shared works, so the sorting decisions are made by the people who grew the lot.