The tasting cup
The tasting cup is a fully regulated immersion: same dose, same grind, same water and same time for each bowl, so that the only difference from one bowl to another is the coffee. It serves to judge and compare coffees, not to drink them.
What does a tasting session fix, bowl by bowl?
Start the scene or choose a stage. The animation simplifies the mechanism; what follows gives the details and the available references.
The coffee is weighed bowl by bowl, 8.25 g for 150 mL to within 0.2 g, and each is ground separately, a little coarser than for a filter. All the bowls start from the same dose and the same grind.
Read the stages without animation
- Weigh and grind each bowlThe coffee is weighed bowl by bowl, 8.25 g for 150 mL to within 0.2 g, and each is ground separately, a little coarser than for a filter. All the bowls start from the same dose and the same grind.
- Pour to the brimWater at 93 °C fills each bowl to the brim. The grind rises and forms a crust that holds in the aromas.
- Break the crustAfter three to five minutes, the crust is stirred three times, nose above the bowl. The aromas trapped under the crust come out all at once; the grounds begin to fall.
- SkimThe particles and oils left on the surface are removed. The liquid clears; the grounds stay at the bottom and keep extracting.
- Slurp as it coolsAt around 70 °C, the coffee is slurped from the spoon, then one goes back over it as it cools. Each pass reads the coffee at a lower temperature, where other qualities are perceived.
To remember: All the bowls start from the same dose, the same grind and the same water: only the difference in the coffee shows.
In history: Widespread in the United States in the early 20th century according to Ukers, in Brazil from 1910 to 1917.
Read the full article and its sources ↓History
Ukers dates the change to about 1900. Before the 20th century, almost all coffees bought and sold in the United States were judged on the appearance of the green or roasted bean; by 1922, “every progressive buyer” had his own equipment for sample roasting and cup testing, and sellers and buyers alike use it to set the value of a lot (source 1, ch. XXIV). The English term is cupping, from cup; here it will be called the tasting session.
The 1922 session already resembles today's. The taster compares the green bean with a standard sample, then the roasted bean, then the smell of the grind. The powder is weighed into each cup “so that the strength is the same,” the water poured at a constant temperature; a crust forms, which is smelled before it is broken, and this test “is held to be of great importance.” Equal sips are slurped, and spat out: “the expert never swallows the liquor.” The test is done blind or open (source 1, ch. XXIV).
Brazil codifies the practice on its own side. Around 1910, a standardized system of cup evaluation was in use in warehouses and ports, and from 1917 the official Santos coffee exchange classified coffee by the cup, on a scale running from “strictly soft” to “Rioy” coffees (source 2).
The modern protocol dates from 2004. In 2024, the SCA, the international specialty coffee association, replaced it with standard 102-2024, which repeals “the SCA cupping protocol (2004 and all later editions)” and a series of older standards on water, grind, roasting, spoons and tables (source 3). The standard now also covers the tasting of coffees prepared otherwise, filter or French press, for descriptive evaluation (source 3).
The motion
The coffee is roasted to a medium degree, aimed at 63 on the Agtron “Gourmet” scale, air-cooled with no water quench, then stored protected. The bowls are of tempered glass or ceramic, 200 to 350 mL and 75 to 90 mm in diameter at the rim, all identical. 8.25 g of beans are weighed per 150 mL of bowl capacity, to within 0.2 g, and each bowl is ground separately, so that 70 to 75% of the grind passes an 850-micron sieve, a little coarser than for a paper filter; a few beans of the new sample first purge the grinder (source 3).
The dry grind is smelled, then water at 93 °C, to within 3 °C, is poured to the brim. A crust forms; it is smelled intact, left three to five minutes, then broken by stirring about three times, nose above the bowl. The surface particles and oils are skimmed, rinsing the spoon between bowls. When the coffee has fallen to around 70 °C, it is slurped noisily from the spoon to coat the tongue and palate, spat out, and revisited at least three times as it cools below body temperature (source 3).
The settings
- Grind70 to 75% passing US sieve no. 20 (850 µm), a little coarser than a paper filter (source 3).
- Dose8.25 g of beans per 150 mL of bowl capacity, to within 0.2 g, weighed bowl by bowl (source 3).
- Brew ratio55 g per liter of capacity, or about 1:18 (source 3, calculation).
- TemperatureWater at 93 °C, to within 3 °C; tasting from about 70 °C down to below body temperature (source 3).
- TimeCrust left intact three to five minutes (source 3).
- PressureAtmospheric.
What it has going for it
- Each bowl receives exactly the same treatment, so that the differences perceived come from the coffee and not from the preparation; the standard demands it even in roasting (source 3).
- The equipment is rudimentary, bowls, a scale, a grinder and a kettle, and an entire table of samples is judged in one session.
- Reading at several temperatures reveals what a single sip would hide, since each pass is made on a colder coffee (source 3).
- It is a common language: as early as 1922, buyers and sellers used it to discuss the value of a single lot (source 1, ch. XXIV).
What is held against it
- It is not a drink: left on its grounds, the bowl tends toward an extraction of 23.9% for a caffeinated coffee, beyond the 18 to 22% window aimed at for a drinking cup (source 4).
- Tasting is from bowls shared by several tasters; the standard provides a variant in which each transfers the coffee to his own vessel to avoid direct contact (source 3).
- The session requires spitting out each sip, otherwise a long table of samples would make one absorb too much caffeine (source 3).
- The result depends on the taster and on calibration, and any departure from the protocol must be declared to the parties (source 3).
What it gives in the cup
The bowl is more extracted than an ordinary cup. In trials run according to the protocol, on a grind of 548 microns median size, 180 g of water at 99 °C and 9 to 14 g of coffee, crust pushed down at four minutes then ten minutes of rest before filtration, equilibrium extraction reaches 23.9% for four caffeinated coffees from light to very dark roast, and 22.2% for a decaf (source 4).
Two results of the same study justify strictness on the dose and flexibility on the rest: the final concentration is inversely proportional to the brew ratio, and four different roasts give indistinguishable equilibrium concentrations (source 4). The dose therefore sets the strength of the bowl, which explains why it is weighed to within 0.2 g (source 3). The measurements were made on the day of roasting, with no degassing rest (source 4).
Anecdotes
- The 1922 taster spits into an hourglass-shaped brass spittoon that comes up to his waist (source 1).
- The 1922 tasting table turns by hand: a tray three and a half feet in diameter, a scale at the center, and a separate stand that keeps one cup still while the tray turns (source 1).
The sources for this sheet
- William H. Ukers, All About Coffee, New York, The Tea and Coffee Trade Journal Company, 1922 (local transcription 1922_Ukers_All_About_Coffee_UTF8.txt), ch. XXIV (cup test, equipment, illustration of the revolving table) · online · primary
- Jonas Ferraresso, “COB: The Complex History of the ‘Brazilian Official Classification’ System,” Daily Coffee News, February 21, 2019 · online · press
- Specialty Coffee Association, SCA Standard 102-2024, Coffee Value Assessment: Sample Preparation and Tasting Mechanics, 2024 · online · primary
- J. Liang, K. C. Chan, W. D. Ristenpart, “An equilibrium desorption model for the strength and extraction yield of full immersion brewed coffee,” Scientific Reports, 11, 2021, 6904, doi:10.1038/s41598-021-85787-1 · online · primary