And the good news is you can do a rough version of it at your kitchen counter tonight with no equipment you do not already own.
What cupping actually is
Every sample gets prepared exactly the same way. Same dose, same grind, same water at the same temperature, same steeping time. That rigidity is the entire point. If two coffees get brewed differently, then any difference you taste might have come from the brewing rather than from the coffee, and the whole exercise is worthless.
The protocol goes down to the vessel. The SCA specifies tempered glass or ceramic bowls between 207 and 266 millilitres, with a wide mouth so your nose has clear access, and deep bowled spoons that will not add any flavor of their own1. A crust forms on top of each bowl as the coffee steeps. You break it with the spoon and put your nose right in as it releases. Then you slurp, hard, because spraying the coffee across your whole palate is how you get it onto all of your tongue at once.
How coffee gets scored
The SCA 100-point scale is the thing that formally defines what specialty coffee even is, and it goes back to 19822.
Ten attributes get assessed: aroma, flavor, aftertaste, acidity, body, balance, uniformity, clean cup, sweetness and overall impression. Then defects get subtracted. A taint costs two points per affected cup and a fault costs four1.
Eighty points is the line. Below eighty a coffee is commodity grade. At eighty or above it is specialty. From there, 85 to 89.99 grades as excellent and 90 or above as outstanding, which is rare enough that most specialty coffee lives somewhere between 80 and 881. The numbers sound clinical but the gap between an 84 and an 87 is a real difference in clarity and complexity, and it shows up directly in what a lot costs us.
Is the score the whole story?
Increasingly no, and the SCA says so themselves.
They have been piloting a replacement called the Coffee Value Assessment, on the grounds that the old protocol was built to produce a single quality score, while a lot of the industry now cares more about what a coffee is actually like than about its number3. The new system splits the descriptive assessment away from the affective one, and it deliberately hides information about the coffee from the person assessing it, so that knowing the farm or the price cannot push the palate around3.
So when you see a score on a bag, know what it is telling you. It tells you a coffee cleared a bar. It does not tell you whether you are going to like it.
Try this
Cup two coffees properly instead of brewing them. Grind both the same, put the same dose in two mugs, pour water just off the boil, wait four minutes. Break the crust with a spoon and get your nose in there. Then slurp off the spoon rather than sipping. You will notice more in those ten minutes than you will in a month of ordinary drinking.