Roughly one person in four is wired to experience certain bitter compounds at an intensity the rest of the table never receives, and a sizeable share can barely detect the test chemical at all. Those are the figures Jessica Easto reports in How to Taste Coffee, and they explain a lot of arguments about whether a given cup is "too bitter." The word for the sensitive end of that range is supertaster, and if you have ever suspected your palate is either specially gifted or genetically broken, here is the direct answer: the supertaster test measures something real, the something is narrower than the name suggests, and it matters far less to your coffee than the training you have or have not done. Your palate is not the ceiling. Your experience is.
What the test actually measures
The standard test is a small strip of paper carrying one of two bitter compounds, phenylthiocarbamide or 6-n-propylthiouracil, PTC and PROP for short. Easto explains the setup: humans have about twenty-five known receptors for bitterness, controlled by our genes like eye colour or height, and not everyone's receptors can detect every bitter compound. PTC and PROP are used as the measuring stick because responses to them split the population so cleanly.
Maxwell Colonna-Dashwood describes what the split looks like in practice in The Coffee Dictionary. Hold the strip on your tongue for a few seconds and one of two things happens. You taste paper, and nothing else. Or you react violently, pull a face, rinse your mouth out, and spend a while regretting the experiment. Same paper, different genes.
Easto's numbers put shape on the range: about 25 per cent of people are ultrasensitive to PROP, another 45 to 50 per cent can moderately taste it, and around 70 per cent can taste PTC. The proportions vary between populations, and the research she cites found tasters and non-tasters in every community studied. So the trait is real, measurable and inherited. What it is not is a general-purpose talent score, for reasons that arrive shortly.
The free version of the test
You do not need chemical strips to place yourself on the spectrum, because sensitivity tracks the hardware. Colonna-Dashwood notes that the reaction correlates directly with how many taste buds you carry, and Easto includes a kitchen-table version of the count. Dab a little food colouring on your tongue with a cotton swab, lay over it a strip of paper with a standard hole punched in it, photograph the circle of stained tongue, and zoom in. The dye makes the papillae, the small structures that house your taste buds, stand out as pale bumps. More than thirty-five inside the hole and you count as a supertaster; around thirty-five is typical.
Treat the result the way Easto does: as an interesting evening with friends rather than a diagnosis. Her own results are a useful caution about how messy the category is. Testing herself, she could taste three of the four standard test compounds but not PTC, with no strong reaction to any of them. The tidy word "supertaster" covers a scatter of part-way results like hers, and the researchers she cites acknowledge the identified genes do not fully explain the phenomenon.
What being one actually changes
Sensitivity shapes preference, not skill. The research Easto summarises finds that people at the sensitive end tend toward predictable dislikes: broccoli, spinach and Brussels sprouts read as unpleasantly bitter, dark chocolate and chiles lose their appeal, and PROP tasters, she notes, often avoid black coffee altogether. A 2022 study of Italian coffee drinkers she cites found that people genetically more sensitive to caffeine's bitterness tended to prefer their coffee sweetened, while those more sensitive to sweetness preferred it black.
Read that carefully, because it inverts the flattering assumption. The "super" palate is not the connoisseur's palate. Extra intensity makes bitter drinks harder to enjoy, not easier to appreciate, and the people happily drinking a bracing black cup are disproportionately the ones who taste it less loudly. If you find most coffee too bitter, that is not a failure of sophistication and it will not be fixed by trying harder. It may simply be your receptors doing exactly what they were built to do. The practical move is not to force the intensity down your own throat but to change what reaches it: most bitterness in a cup is put there by the brew, and the sour-or-bitter diagnostic tells you which direction to move. A sensitive taster with a well-run grinder drinks better coffee than a numb one with a bad recipe.
The catch: the strip never tested your nose
Here is the reason the whole question matters less than it seems, and Colonna-Dashwood states it plainly: the supertaster test does not measure the abilities of your nose, and the nose is vital in tasting.
The division of labour runs like this. Your mouth detects the basic tastes, bitterness among them, plus texture. Nearly everything you would actually name in a coffee, the berry, the chocolate, the jasmine, the caramel, arrives through smell, much of it rising into the nasal cavity from inside the mouth as you sip and swallow, a route Easto describes called retronasal olfaction. And the nose is not a five-channel instrument like the tongue. Easto reports research finding humans can discriminate at least a trillion odour stimuli, against a few million colours. The strip on your tongue graded one channel of the narrow system and said nothing at all about the wide one.
So a supertaster result is a statement about the volume knob on bitterness. It is not a statement about your ability to find blackcurrant in a Kenyan coffee, because that ability lives in a different organ, one with its own separate and equally wide person-to-person variation, and one thing more: it responds to practice.
Training beats wiring
This is the strongest claim in Colonna-Dashwood's entry, and he does not hedge it. Is tasting genetic? "Well, no," he writes, although genetic differences exist. Discerning character in food and coffee is an experience-based skill. The people who can name what is in the cup got there by tasting a great deal of coffee, deliberately, and building what he calls a taste library: a stock of remembered references that new coffees can be checked against. He adds a finding that should end any fatalism about fixed palates: sensitivity to things like sugar can be learned, and changes over time. The instrument you were testing is not even stable. It moves with use.
Building the library is mechanical, not mystical. Comparison does the heavy lifting, because a lone cup is judged against wobbly memory while two cups side by side turn a vague impression into an audible difference. When you want more than two coffees on the table under identical conditions, a cupping needs six matching bowls and a spoon, not professional equipment. And start the vocabulary in the mouth rather than the nose: sweetness, body and acidity, which is a structural quality of the cup you can learn to read and to brew for, are shareable judgements two people can agree on, which makes them trainable in a way that "I get elderflower" is not. None of this requires knowing your PROP status. All of it moves your tasting further than the genetics ever will.
What a supertaster result will not do
Say it plainly: the result will not make you a better taster, and a non-taster result will not stop you becoming one. It will not predict whether you can learn to pick a washed Ethiopian out of a line-up, because that is nose work and memory work. It confers no professional standing; the trade's own qualification exams are built on trained, calibrated tasting, not on genetic screening. And the test will not even settle whether you should drink your coffee black or sweet. It only suggests why you already prefer what you prefer.
The honest recommendation, then. Do the taste-bud count once, with friends, the way Easto suggests, and enjoy whatever the photographs show. Then file the result under biography rather than destiny, and spend the money a test kit would have cost on two contrasting bags of coffee. Taste them side by side this week, again next week, and write down what you find. In a month the notebook will have done more for your palate than your genome ever did.