How to build a tasting flight at a small coffee bar: the parts worth your time

A flight is three cups arranged so that one thing changes across them. Done properly it teaches you something in twenty minutes. Done casually it produces three cups of coffee and no information.

What to take away

Choose one axis for the flight and hold everything else still.
Filter material is a real axis, and paper against metal is the easiest place to start.
Grind size changes what reaches the cup as much as roast does.
Three cups is the limit before your palate stops being useful.

Pick the axis first

The axis is the thing that varies. Good axes for a home flight:

Filter Material: Paper vs Metal

Paper filter

Aroma: Caramel, flowery
Oils: Retained
Fines: Retained
Best first flight: Yes

Metal filter

Aroma: Fruity, roasted
Oils: Pass through
Fines: Pass through
Best first flight: No

Filter material.: Paper against metal, same coffee, same grind.
Roast level.: Light, medium, dark from the same roaster.
Process.: Washed, natural, honey from the same origin.
Grind size.: One coffee, three settings, same brewer.
Freshness.: Same coffee at one week, three weeks, six weeks.

Filter material is the best first flight: the difference is large and the cause is obvious. A comparison of four filter methods on one Kenyan specialty coffee found that paper filters produced more caramel and flowery compounds while metal filters gave more fruity and roasted character.

The sensory panel results matched the chemical analysis. Paper retains oils and some fines; metal does not.

Hold the rest still

Everything not on the axis must match: dose, water, water temperature, total brew time. Cup shape and serving temperature too. More demanding than it sounds, this is why a flight works.

Variables to Hold Still

Dosesame to the gram
Watersame type and source
Water temperatureidentical
Total brew timematched
Cup shape and serving temperaturesame
Grind sizedo not change

The same rule governs a two-cup tasting at a station, where the same water and the same grind are what make it a test of the coffee.

Grind is the variable people forget to hold still, and it is not minor.

A study varied roast conditions, grind size and brewing method. It found measured volatile intensity was inversely related to grind size, and water type also affected the volatile profile of the finished brew.

If your three cups used tap water, filtered water and bottled water, you ran an accidental water flight.

The setup

Element / Rule

Cups: Three identical, wide mouth
Dose: Same to the gram
Water: One kettle, one fill
Timing: Brew within five minutes of each other
Serving: Taste all three at the same temperature

Number the cups on the underside and have someone else arrange them if you can. If you are alone, shuffle and taste before you look. The same arrangement works on what you add to a cup rather than on which cup it is, and three ways in one sitting usually shows a default to be habit.

Reading the flight

Taste in order, then reverse the order and taste again. Differences that survive reversal are real. Differences that vanish were probably position effects, which are stronger than most people believe.

Write three words per cup, then one sentence naming the difference between the extremes. Do not try to name a winner during the tasting. Decide afterward, when you have read your own notes.

Repeat the flight that surprised you

If a flight surprises you, run it again on another day before changing your buying, because one flight is a hypothesis. Two agreeing flights are worth spending money on.

Once you know your preferred axis position, the label is what lets you buy it again, and the practical mechanics of fair two-cup tasting are worth getting right first.