SCA Q Grader cheat sheet

SCA green grading uses a 350 g sample; every defect is counted and converted to full-defect equivalents.

Category 1 (primary) defects count at full value; Category 2 (secondary) defects count one-fifth, so five Category 2 equal one full defect.

Specialty grade requires zero Category 1 defects and no more than five Category 2 defects in 350 g.

Category 1 examples: full black, full sour, pod/cherry, medium stone, large stone, foreign matter, fungus damage.

Category 2 examples: partial black, partial sour, floater, immature/unripe, withered, shell, broken/chipped, hull/husk, small stone, sticks, insect damage, water damage.

Green coffee moisture target is roughly 10-12%, with water activity at or below about 0.60.

Bean size is measured in 1/64-inch screens; specialty lots commonly require screen 15 or larger.

Immature or unripe beans appear as pale 'quakers' after roasting because they lack sufficient sugars to brown.

The five basic tastes are sweet, sour, salty, bitter and umami; astringency and pungency are tactile sensations, not tastes.

Orthonasal olfaction is smelling through the nose; retronasal olfaction is aroma rising from the mouth to the nasal cavity during tasting.

SCA olfactory assessment uses coded aroma vials; the Q Grader exam typically uses four sets of six vials.

Aroma families: enzymatic (fruity, floral, herbal), sugar-browning (caramel, nutty, chocolate), dry-distillation (spicy, smoky, resinous).

Olfactory adaptation reduces sensitivity after prolonged exposure; rest, fresh air or a neutral scent restores it.

Detection threshold is the lowest concentration perceived; recognition threshold is the lowest concentration identified by name.

PROP (6-n-propylthiouracil) tasting classifies bitterness sensitivity as non-taster, medium taster or supertaster.

SCA cupping dose is 8.25 g of coffee per 150 mL of water, a ratio of about 1:18.2.

Water should be fresh and filtered at 93°C (about 200°F), with TDS of roughly 125-175 ppm.

Grind medium-coarse; steep 4 minutes, break the crust, skim, then evaluate as cups cool toward about 70°C.

Ten categories are scored up to 10 points each for 100 total: fragrance/aroma, flavor, aftertaste, acidity, body, balance, uniformity, clean cup, sweetness, overall.

Uniformity, clean cup and sweetness each award 2 points per cup across five cups, for 10 points per category.

Scores run 6-10 in 0.25 increments: 6 good, 7 very good, 8 excellent, 9 outstanding, 10 exceptional.

Defects are deducted per affected cup: a taint costs 2 points and a fault costs 4 points.

Specialty classification requires a final score of 80.00 or above.

SCA triangulation presents six cups: three of one coffee and three of another; the cupper identifies the odd group.

With a 3/3 six-cup set, random guessing succeeds once in 20 attempts, so one correct answer is significant at the 5% level.

The classic triangle test uses three cups, two identical and one different; the task is to identify the odd cup.

The duo-trio test presents a reference plus two coded samples; the cupper selects the sample matching the reference.

All samples must match in dose, grind, water, roast level and temperature; only the variable under test differs.

Rinse spoon and palate between sets and limit sets per session to control sensory fatigue.

Ascending forced-choice (ASTM E-679) is a standard method for estimating discrimination thresholds.

Citric acid reads as bright lemon/citrus sourness and is prominent in high-grown washed arabica.

Malic acid reads as apple or stone-fruit sourness and is smoother than citric acid.

Lactic acid gives creamy, dairy-like sourness and rises with microbial fermentation.

Acetic acid gives vinegar-like sharpness; it is volatile and a defect marker at high levels.

Tartaric acid gives grape or wine-like sourness and occurs in small amounts.

Quinic acid is bitter and astringent; it forms as chlorogenic acid degrades during roasting.

Phosphoric acid is inorganic and reads as bright, mineral or metallic acidity.

Perceived acidity depends on total acid concentration and the ratio among acids, not on pH alone.

SCA sample roasting targets roughly 8-12 minutes total with a charge of about 100-150 g.

First crack typically occurs at about 196-205°C bean temperature.

Development time after first crack should be about 20-25% of total roast time.

Agtron color: light roast above about 70, medium about 55-60, dark below about 45.

Roast defects include scorching, tipping, facing, baked/flat, underdeveloped and charred beans.

Quakers are pale unripe beans that fail to brown because of insufficient sugars.

Lighter roasts preserve acidity and origin character; darker roasts add body and bitter, carbonated notes.

SCA recommends resting a sample roast about 8-24 hours before cupping.

Typica is a tall, low-yield, clean and sweet traditional cultivar from which many varieties descend.

Bourbon is a Typica mutation with rounder beans, good sweetness and balanced acidity.

Gesha originated in Ethiopia and is famous in Panama for jasmine, bergamot and floral notes at high altitude.

SL28 and SL34 are Kenyan selections known for blackcurrant-like acidity and drought tolerance.

Pacamara is Pacas x Maragogype, producing very large beans with a distinctive savory-floral character.

Caturra and Catuai are dwarf mutations widely planted in Brazil and Colombia for dense planting.

Washed processing removes fruit before drying, yielding clean, bright, higher-acidity cups.

Natural (dry) processing dries the whole cherry, giving fruity, heavier-bodied cups with higher defect risk.

Wet-hulling (Giling Basah) is used in Sumatra and yields low-acid, earthy, full-bodied coffee.

Q Grader certification is valid for three years and is maintained through recalibration.

Graders must disclose conflicts of interest and recuse themselves from scoring samples in which they have a stake.

Samples are coded blindly; origin and producer identity are withheld during cupping.

Scores must be independently determined; discussing scores during a session compromises validity.

Accepting gifts, favors or payments to influence a grade violates the code of ethics.

Client samples, scores and business information are confidential.

A specialty lot must score 80.00+ with zero Category 1 and no more than five Category 2 defects per 350 g.

Certification requires passing every module; a failed module is retaken at a later session.