What counts as a defect in green coffee?

Physical faults such as black, sour, insect-damaged, broken or fungus-damaged beans, and foreign matter. Grading systems weight serious defects more than minor ones.

What is a good cupping score?

On the widely used 100-point scale, coffees scoring 80 and above are generally described as specialty. Scores are only comparable within one protocol and one team.

Grading and cupping green coffee before you buy

A buying decision needs two kinds of evidence: what the green coffee looks like in your hand, and how it tastes on the table. A practical grading and cupping routine for roasters.

8 min read Updated 9 October 2026

Grading is a physical inspection of green coffee; cupping is a standardised tasting of roasted samples. Together they tell you whether a coffee is worth its price and whether the delivered lot matches what you approved.

Physical grading

Take a representative sample. Specialty Coffee Association (SCA) grading uses 350 g of green coffee.
Smell it. Green coffee should smell fresh, grassy or hay-like; musty, earthy or fermented smells are a warning.
Measure moisture, and water activity if you can.
Separate defects by hand on a neutral surface: full black or sour beans, fungus damage, foreign matter and insect damage are serious; broken, shell, floater and partly damaged beans are lesser. The SCA's green grading handbook groups them into Category 1 and Category 2 defects with conversion counts.
Count defects as full-defect equivalents using the handbook's ratios.
Check screen size with sieves; screen sizes are measured in 64ths of an inch, so screen 18 means holes of 18/64 inch. Uniform size roasts more evenly.
Record the results against the lot reference.

Specialty grade, in short

Under SCA green grading, specialty grade coffee has zero Category 1 defects and no more than five full defects in a 350 g sample, along with moisture within the accepted range and a clean cup. Check the current SCA standard for the full criteria.

Cupping for buying

Cupping protocols fix every variable except the coffee. The SCA protocol, widely used in the trade, sets a light-medium sample roast, a ratio of 8.25 g of coffee to 150 ml of water, water just off the boil at about 93°C, a break of the crust at around four minutes, and five cups per sample to check uniformity. Follow one protocol every time so scores are comparable across months.

What to assess	What it tells a buyer
Fragrance and aroma	Freshness and character; staleness shows early
Flavour and aftertaste	Whether the coffee fits the role on your menu
Acidity and body	Brightness and weight, for blending decisions
Balance and sweetness	How it will behave across roast levels
Uniformity and clean cup	Whether one cup in five is defective, a lot problem
Defects	Taints such as mustiness, ferment or phenol: reasons to reject

Turning scores into decisions

A score is only useful against price and purpose. Keep a simple sheet per coffee role: price per landed kilo, score, key descriptors, and whether it worked in the blend or on the bar. Over a season you will see which coffees earn their premium.

Cupping routine

Cup blind, with a known reference coffee on the table
Two people cupping where possible, scores compared
Arrival samples cupped against the approved sample
Results stored with the lot, not in a notebook

Where Roastnet helps

Questions roasters ask

What counts as a defect in green coffee?: Physical faults such as black, sour, insect-damaged, broken or fungus-damaged beans, and foreign matter. Grading systems weight serious defects more than minor ones.
What is a good cupping score?: On the widely used 100-point scale, coffees scoring 80 and above are generally described as specialty. Scores are only comparable within one protocol and one team.

Official sources

Specialty Coffee Association: Protocols and best practices

Rules change. These sources were checked on 9 October 2026; always confirm the current position with the body that publishes them before you act.