SCA Q Grader key terms

A serious green coffee imperfection - such as a black bean, sour bean, fungus-damaged bean or piece of foreign matter - that counts as one whole defect against a 300-gram sample. Any full defect disqualifies a lot from specialty grade.

A minor green coffee imperfection such as a broken bean, husk, floater, immature bean or slight insect damage. Five secondary defects together equal one full defect when a 300-gram sample is graded.

A full defect in which the bean is dead, dark and opaque through the centre, usually from over-fermentation, frost or disease. It typically produces harsh, phenolic or medicinal flavours in the cup.

A full defect: a bean with a yellowish to reddish-brown, vinegary-smelling interior caused by fermentation or bacterial activity. It usually gives sharp, sour, fermented or dirty notes when cupped.

A full defect where mould or fungal growth has affected the bean, visible as yellowish, brownish or powdery patches. It typically causes musty, earthy or medicinal flavours in the cup.

A measure of the free, unbound water in green coffee on a 0 to 1 scale. Specialty standards call for roughly 0.55 to 0.60; higher values favour mould growth and stale flavours.

An immature or underdeveloped bean that stays pale after roasting because it lacks the sugars needed for browning. In the cup it gives papery, peanut-like or straw notes and breaks uniformity.

A set of standardised smell vials, such as the 36-aroma Le Nez du Cafe set, used in Q training and exams to build and test recognition of coffee aromas like jasmine, citrus, caramel and earthy notes.

The lowest concentration of a substance that a taster can reliably notice as different from the blank, even without being able to name it. It sits below the recognition threshold.

The lowest concentration at which a taster can correctly identify what a substance is, for example naming vinegar as vinegar. It is always higher than the detection threshold.

The temporary drop in sensitivity that follows repeated or prolonged exposure to a stimulus such as coffee aroma. Tasters manage it with breaks, fresh air and by limiting how many cups they evaluate.

The standardised procedure for evaluating coffee: 8.25 g, plus or minus 0.25 g, of ground coffee per 150 ml of water at about 93 degrees Celsius, a four-minute steep, breaking the crust, then slurping and scoring as cups cool.

A cupping attribute scored across five individual cups, giving two points per cup for a maximum of ten. Any cup that differs from the rest through defect, taint or different character loses points.

A cupping attribute reflecting the absence of off-flavours such as ferment, mould, phenolic, earthy or chemical notes. Each of five cups earns two points if clean, for a maximum of ten.

A cupping attribute rewarding pleasant sweet flavours such as fruit, caramel and honey, and the absence of sourness, astringency or green notes. Two points are given per cup, up to ten.

On the SCA cupping form, a taint is a mild off-flavour costing two points per affected cup, while a fault is a strong off-flavour costing four points per cup. Deductions are subtracted from the final score.

The cupping outcome in which a coffee scores at least 80.00 points on the 100-point scale, shows no faults and meets attribute minimums. Coffees scoring below 80 are graded as non-specialty.

A discrimination test in which each set has three cups, two identical and one different, and the taster must identify the odd cup. Q exams use it to test sensory acuity and consistency.

A family of sensory tests, including triangle, duo-trio, tetrad and paired comparison, that ask whether samples differ rather than how they rate on attributes. Results are analysed statistically for perceptible differences.

A discrimination test using four samples, two of one kind and two of another, which the assessor groups into two similar pairs. It extracts more information per tasting than the triangle test.

The most common organic acid in arabica coffee. It contributes bright, citrus-like sourness and sweetness, and higher levels are associated with washed, high-grown coffees.

An organic acid in coffee linked to a clean, apple-like or pear-like sourness. Its level varies with variety, ripeness and processing, and it decreases during roasting.

A volatile organic acid produced mainly by fermentation. In small amounts it adds fruity complexity; in excess it creates a vinegary, sharp or fermenty defect.

An organic acid formed when bacteria ferment sugars, often in anaerobic or extended fermentations. It adds a soft, creamy, yoghurt-like sourness and can increase perceived body.

An acid that increases as chlorogenic acids break down during roasting and as coffee stales. It is linked to astringency, bitterness and the harsh lingering sourness of old coffee.

A drying, puckering, rough sensation in the mouth caused by compounds such as tannins and chlorogenic acid derivatives binding with salivary proteins. It is a tactile sensation, not a basic taste.

The audible popping stage of roasting, around 196 to 205 degrees Celsius bean temperature, when moisture and gases burst out of the bean as it expands. It marks the start of a roast suitable for cupping.

The faster, quieter crackling that follows first crack as the bean's cellulose structure fractures. Coffees roasted into second crack are dark and are not used as SCA cupping samples.

An instrument scale that measures roast colour, from roughly 25 for very dark to 95 or more for very light. SCA cupping samples are roasted to a medium level, often quoted as about 58 in ground form.

The standard for preparing cupping samples: batches of about 100 to 150 g roasted in 8 to 12 minutes, reaching first crack and finishing before second crack, then rested before evaluation.

The percentage of total roast time spent after first crack begins. Too short a ratio gives underdeveloped, grassy coffee; too long gives flat, baked flavours with muted acidity.

The species Coffea arabica, grown mostly at higher altitudes and valued for higher acidity, lower bitterness and complex aromatics. It contains roughly half the caffeine of robusta.

A high-value arabica variety originally from Ethiopia, known for jasmine, bergamot and stone-fruit aromatics and for record auction prices in Panama, Colombia and Ethiopia.

Removing the cherry skin and pulp, then fermenting and washing the mucilage off the seeds before drying. It typically gives clean, bright cups that show variety and origin clearly.

Drying whole coffee cherries with the fruit still on the seed, then hulling the dried fruit later. It tends to give heavier body, fruity or fermented flavours and more variation between cups.

Drying coffee with some mucilage left on the parchment, graded white, yellow, red or black by how much remains. It gives sweetness and body between washed and natural styles.

An Indonesian method, known as giling basah, in which parchment is stripped while the bean is still high in moisture, then dried. It yields heavy body, low acidity and earthy, spicy character.

A periodic exercise in which a certified Q Grader cups a set of reference coffees and must score them close to agreed target scores. It confirms the palate still matches the SCA scale.

The rule that a Q Grader licence must be renewed periodically, normally every three years, by passing calibration plus the required written and sensory examinations again.

The professional conduct rules that Q Graders agree to follow, covering honesty, confidentiality, conflicts of interest and the fair, unbiased grading of every coffee and client.