Sensory Evaluation of Coffee — Cupping Part I
There are many categories of evaluating coffee quality—from green bean density, moisture and defects, to brewed cup. In this section, for now, the focus is on the sensory evaluation of brewed coffee referred to as, "cupping." Our aim is to help make this sometimes intimidating exercise approachable for anyone and urge you to make this practice an important part of your ongoing learning.
The Big Picture
Cupping coffee is about qualifying (and quantifying) coffee quality using your mouth and your nose—taste and olfactory. The process conforms to consistent methodology that makes it possible to accurately communicate coffee nuance with other professionals and enthusiasts.
Above all, we ascribe to three maxims when it comes to evaluating coffee: Cup, Compare and Compose.
First, Cup, cup, cup. Often. If you thoughtfully prepare and carefully evaluate coffees regularly, you will hone your tasting skills. There are certainly physiological differences among people that make it easier for some to detect subtle nuance in taste and aroma than others, but most everyone can become competent coffee tasters. Do it regularly and your skill will grow.
Secondly, Compare with other coffees. Since coffee quality is about comparative merits against other cups, tasting side-by-side will help you notice aromas, tastes and "Ah-ha" features that you may otherwise miss. Saying a coffee has bright acidity means it has bright acidity compared to something else. This doesn't mean comparing 20 coffees in one sitting which can be overwhelming for the uninitiated, but recognizing the importance of evaluating in context.
Thirdly, Compose your notes and reflections and keep those records. Writing down your impressions will force you to articulate your senses into words and scores. Returning back to those notes will also help you remember and understand.
The Tools
The basic tools used by professionals include:
- Cupping bowl or glass which holds between 7 and 9 fl ounces (207ml to 266ml);
- Cupping spoon;
- Scale (to measure 8.25g of coffee per cup);
- Grinder capable of consistent grind (burr grinder);
- Color metering device (Agtron or comparable);
- Timer
- Hot water, forms and pencils
The particularity for all this is about developing uniformity so all variables except for the coffee itself have been controlled as best as possible. With this in mind, one can cup coffee at home without all these pieces in place. For instance, you don't need a color meter, but you want to insure your roasts are consistent and aiming toward a fairly light roast so all the coffee characteristics are intact.
The Steps
Preparation
The steps outlined below are for semi-casual, home cupping and sufficient for most non-professional purposes. The SCA standards that are followed in professional circles can be found here.
Roast your samples light, with a roast cycle between 8-12 minutes. SCA specification is for Agtron color of 63.0 on the "Gourmet" scale. You can refer to color charts to approximate this.
Find glasses or cups that are all the same size and weigh out whole beans into each (trying to follow the measurements noted above). Arrange at least 2 cups of each coffee sample (SCA standard is to use 5 cups of each). This is to ensure that any defect which may be present in one cup doesn't give a false evaluation of the coffee.
Begin heating the water to 200℉.
While you're heating the water, grind the coffee to a medium grind size. Before grinding one of your weighed samples, "rinse" the grinder by passing several beans of that same (but not measured) coffee through your grinder first, then toss. You're trying to avoid any residual coffee grounds in the grinder from one sample contaminating the next.
Once all the coffee is ground, you're ready to begin assessing your coffees.
The Cupping
In this overview, we are providing basic steps to get you started evaluating coffees. We will follow up with more detail (and some science) in other posts to help you evaluate nuance more accurately. But because we believe skill develops best from practice, it's important to get started, albeit with good habits.
With clean hands, free from any soap residue or odor, sniff each bowl of ground coffee, inhaling deeply. This is the Dry Fragrance. Move from one coffee to the next, noting any differences you detect and try to form those differences into descriptive terms.
Compose your notes.
Start a timer for 4 minutes as you begin filling each cup with heated water. Move quickly and fill all cups the same amount, being careful to wet all the coffee grounds. While you're doing this, fill another cup or so with hot water which you will use for rinsing the spoon during tasting. Leave these brewing coffees undisturbed until the 4 minutes has elapsed.
After your 4 minute timer has expired, take your round, deep spoon and gently break through the crust of grounds which is floating on the top of the cups of coffee. Start with the coffee you filled with water first. 
As you do "break" each crust, position your nose as close to the spoon entry point as possible. In three gentle stirs of the grounds, smell the coffee aroma as it escapes the crust and emanates from your spoon. Concentrate on what you are smelling and move from one sample to the next, dipping to rinse your spoon in a cup of hot water as you progress. This is the coffee Aroma.
Compose your notes.
After breaking all crusts, carefully skim any remaining grounds from the top of each sample and discard. You want the surface to be reasonably free from grounds to avoid slurping these during the tasting phase.
Let the coffee cool for a few minutes before tasting so you don't burn your tongue.
When the coffee reaches a safe temperature, it's time to taste. If you're reading this you've no doubt done, seen or heard about this part of the whole undertaking. Take your cupping spoon in one hand and an empty cup in the other, then dip into the coffee using the edge of the spoon so as not to disturb the grounds below. Scoop up some coffee without filling the spoon to the brim.
Putting the spoon to your lips, vigorously "slurp" the liquid into your mouth so as to "spray" the coffee throughout your mouth, allowing different parts of your tongue (and olfactory senses) to experience/taste the coffee. There is no "polite" or gentle way to do this. The more noise you're making probably means the better you're doing this. Swoosh the coffee around in your mouth a bit, mixing with air while tasting, then expectorate (spit) the coffee into the empty cup that's in your other hand.
Move from one sample to the next, dipping your spoon to rinse between each sample. Note the differences in the various characteristics which we briefly touch on below.
Compose your initial tasting notes. We say, "initial" here because it's important to go back to the coffee when it is more tepid and even cool, to taste again. The characteristics will evolve and reveal differently as the coffee cools. 
Evaluating the Taste
The Official SCA Cupping Form is the industry standard form/tool relied on internationally for cupping. In many ways, we prefer (and recommend) using a similar form developed by longtime coffee professional, Willem Boot. This form covers the same, 10 aspects of evaluating/scoring coffee quality, but the Boot Coffee form lists various aroma and taste qualifying terms often found in coffee, and in relation to particular aspects of a coffee's evaluation.
For instance, in the category of Acidity, terms ranging from Delicate to Nippy to Tart to Winey are included as considerations. While nothing like a complete list of what you may find, these help the new and experienced taster home in on aspects of the coffee they may expect to find. We find this is also helpful when returning back to these records of coffees because they end up containing more descriptive note data.
If you use each category in this form as a list of possibilities, you will find that you will steadily begin to develop a skill in detecting these and similar attributes, while building a vocabulary that describes different parts of the coffee drinking experience. How does a "Creamy" mouthfeel differ from an "Oily" mouthfeel helps you understand and describe something more than simply, a "light" or "heavy" mouthfeel.
As you are developing this skill, it can be helpful to evaluate each coffee sample, one category at a time. Work through each sample focusing on "Flavor" first, compose your notes, then circle back and evaluate Aftertaste of each, composing your notes before moving on to Acidity, etc.
And, again, as you move down the table, comparing sample against sample, you will suddenly pickup on differences in each coffee that are far more nuanced that you would have believed you were capable of detecting. You will also find that as you discover more of these nuances, your taste for those nuances in coffee will likely evolve. And you'll have more exciting discoveries to share with others!