10.1 SCA Standard Cupping Protocol

10.1 SCA Standard Cupping Protocol

Quick Answer: The SCA cupping protocol is the standardised sensory evaluation method used worldwide to grade, price, and analyse coffee. Since November 2024 the governing document is SCA Standard 102-2024, Coffee Value Assessment: Sample Preparation and Tasting Mechanics, which replaced the 2004 SCAA Cupping Protocol. It prescribes a brew ratio of 8.25 g of coffee per 150 mL of vessel capacity (0.055 g/mL, ±0.2 g per cup), water poured at 93 ± 3°C, cupping-level roast defined as ground CIELAB L* 26–29 (≈ Agtron/SCA tile #65, roast-meter target Agtron Gourmet 63), vessels of 200–350 mL with a 75–90 mm top diameter, and a grind where 70–75% passes a 20 US-standard mesh sieve (850 µm). The crust rests unbroken for 3–5 minutes, is broken by stirring three times, is skimmed, and liquoring begins once the brew cools to about 70°C.

Cupping is the bedrock sensory methodology of the global coffee industry. Unlike standard consumer brewing methods—such as pour-over drip or espresso—cupping relies on direct immersion without paper filtration or mechanical pressure. By removing brewing variables and enforcing precise standardized parameters, cupping allows coffee buyers, roasters, and baristas to evaluate the intrinsic physical and sensory attributes of a coffee bean on an objective, reproducible scale.

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Standardized Parameters & Physical Specifications

To eliminate evaluation bias across international laboratories, the SCA Cupping Protocol dictates rigid physical standards for sample preparation, water chemistry, vessel geometry, and particle size distribution.

1. Sample Roast Level & Preparation

Sample roasting for cupping is fundamentally distinct from production roasting. The objective is to expose intrinsic agricultural flavors without imparting roast-driven flavors such as caramelization or pyrolytic smokiness. SCA-102-2024 defines cupping-level roast in colorimetry terms: the ground coffee shall read CIELAB L* 26–29, corresponding approximately to Agtron/SCA Roast Color Classification tile #65, or a roast-meter target reading of 63 on the Agtron "Gourmet" scale. (The older 2004 protocol's "Agtron 58–63 ground / 48–53 whole bean" wording is superseded; if an exam question quotes it, it is quoting the retired form.) Samples are air-cooled without water quenching, stored airtight in a cool dark place, and rested 8 to 24 hours before cupping. Under- or over-developed, burnt or baked roasts must be discarded and the batch repeated.

2. Vessel Specifications & Ratio Precision

Cupping vessels must be identical in volume, dimensions, and material across all samples in a session. SCA-102-2024 specifies tempered glass or ceramic bowls of 200 mL to 350 mL with a top diameter of 75–90 mm. Crucially, the dose is calculated from the measured capacity of the specific cup model, not from a nominal pour volume: fill the vessel to the rim with room-temperature water, weigh it, treat 1 g as 1 mL, then dose at 0.055 g of coffee per mL.

Each cup is weighed separately on a scale accurate to 0.1 g or better, with a permitted tolerance of ±0.2 g per cup (a single coffee bean weighs enough to matter).

3. Particle Size (Grind Standard)

Grind size directly dictates extraction surface area and steep kinetics. The SCA protocol requires a coarse particle distribution: 70% to 75% of ground particles must pass through a U.S. Standard size 20-mesh sieve (sieve opening of 850 micrometers). The sample is ground as close to cupping time as practical. Each cup is ground individually, and the grinder is purged with a small charge of the new sample before the session to displace grounds retained from earlier samples.

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The 5-Phase Cupping Evaluation Timeline

Sensory evaluation follows a chronologically controlled process divided into five distinct operational phases. Panellists must strictly adhere to time intervals to ensure consistent aromatic and flavor release.

 [ Phase 1: before pour ] ──> Dry Fragrance (assess ground coffee as soon as practical)
 [ Phase 2: 0:00 ]         ──> Hot Water Pour (93 +/- 3 C poured to the rim; crust forms)
 [ Phase 3: 3-5 min ]      ──> Crust Break & Wet Aroma (stir the crust 3 times; inhale)
 [ Phase 4: after break ]  ──> Skimming (remove grounds and oils with one or two spoons)
 [ Phase 5: from ~70 C ]   ──> Liquoring / Slurp Tasting (taste as the brew cools)

Phase 1: Dry Fragrance Evaluation (as soon as practical after grinding)

Once each sample has been ground into its own dry cupping bowl, panellists evaluate the dry fragrance — the aromatic gases released from dry grounds. Cuppers gently shake the bowl, place their nose directly over the vessel, and record aromatic intensity and qualitative notes (floral, fruity, nutty). SCA-102-2024 does not set a fixed clock here; it requires only that fragrance be assessed as soon as it is practical, because volatile monoterpenes dissipate quickly.

Phase 2: Hot Water Pouring (Time 0:00)

Water at 93 ± 3°C is poured from a spouted kettle or carafe directly onto the dry grounds, filling the bowl to the rim so that every particle is saturated. The grounds float to the surface and form a dense insulating seal known as the crust. The coffee steeps undisturbed while volatile organic compounds and thermal energy are trapped beneath it.

Phase 3: Crust Break & Wet Aroma (3 to 5 Minutes)

The crust is left unbroken for 3 to 5 minutes, then broken. Bringing the nose within a few centimetres of the bowl surface, the cupper pushes a cupping spoon through the crust three times, stirring back and down. As the crust breaks, a burst of concentrated trapped volatile aromatics — aroma — is released, and the panellist inhales deeply. Aroma is scored from both the undisturbed crust and the break itself. Every cupper at the table should get the chance to break at least one cup of each sample.

Phase 4: Skimming Surface Grounds

Once all the cups' crusts on a table have been broken, the floating foam, grounds, and oils on each surface are removed and discarded. Using one or two clean cupping spoons in a smooth sweeping motion, cuppers skim the top layer into a dump bucket, taking care not to agitate the settled coffee bed at the bottom of the bowl. In practice this lands roughly 8–10 minutes after the pour, but the trigger in the standard is all crusts broken, not a stopwatch reading.

Phase 5: Liquoring — Slurp-Tasting Across Temperature Waves

The brew is allowed to cool to about 70°C before liquoring (tasting) begins — typically around 10 to 12 minutes after the pour. Cuppers dip a cupping spoon into the liquid and slurp the coffee forcefully into the mouth. Forceful aspiration sprays fine liquid droplets across the entire oral cavity and soft palate while driving volatile organic compounds upward into the nasal cavity via retronasal olfaction. Tasting continues across three cooling stages down to room temperature (21°C / 70°F):

• Hot Stage (70°C / 160°F): Evaluation of primary Flavor and Aftertaste.
• Warm Stage (60°C – 45°C / 140°F – 113°F): Evaluation of Acidity, Body, and Balance.
• Cool Stage (37°C – 21°C / 98°F – 70°F): Evaluation of Uniformity, Clean Cup, Sweetness, and Overall score.

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Sensory Physics of Aspiration & Olfaction

The characteristic "slurp" during cupping is not merely an industry tradition; it is grounded in fluid dynamics and sensory physiology. Forceful inhalation of liquid combined with air serves two essential functions:

1. Aerosolization: Rapid fluid acceleration creates micro-droplets, expanding surface area contact across the 10,000 gustatory taste buds on the tongue to detect basic tastes (sweetness, sourness, bitterness, saltiness, and umami).
2. Retronasal Volatilization: Body heat and turbulent airflow vaporize lipophilic aroma molecules, carrying them up the pharynx into the olfactory epithelium. Because up to 80% of perceived coffee flavor is derived from olfactory detection rather than tongue gustation, proper aspiration technique is vital for accurate scoring.