What Your Coffee Says About You, and What It Does Not

Search for what your coffee says about you and you will find plenty of lists. Black coffee means you are no-nonsense, a flat white means you are creative, and so on down the menu. I enjoy them the way I enjoy horoscopes, a little and without believing a word.

A cup can tell you things. It tells you fewer and smaller things than the lists promise, and almost never anything on its own. I try to build Daily Holmes cases on the same rule: a cup is evidence of a habit only when something else in the picture says the same thing. Two old cases come up below, answers and all, so play The Welcome and Move-In Ready first if you want to.

The cup

A paper cup with a café's name on it says the person was near that café recently, or someone brought them one. A reusable cup with a dented base has made a lot of trips. I would read that as a daily habit, though the dents could be years old and the cup only came out of the cupboard this morning. A mug that says WORLD'S BEST GRANDAD is good evidence that somebody once gave it as a present, and that it survived. It says nothing about who drinks from it now. The best evidence on a takeaway cup is the name on the side, and even that is only what someone said at the counter, spelt by a person in a hurry.

The order

The order is where the quizzes live, and what it supports is narrow: what this person likes, and sometimes what they cannot have. Oat milk might be a dairy problem, or just the last carton in the office fridge. A decaf at four in the afternoon might be someone who sleeps badly, or someone who likes decaf. A flat white tells you the café makes flat whites.

Jumping from the order to the person is what cold readers do for a living. In 1948 the psychologist Bertram Forer gave his students a personality test, then handed each a sketch supposedly written for them alone. Everyone got the same sketch, put together mostly from horoscope lines, among them "You have a great need for other people to like and admire you". Asked how well it fitted, on a scale of nought to five, the class gave it a little over four on average.

In The Full Facts Book of Cold Reading, Ian Rowland calls one move the Rainbow Ruse: credit someone with a trait and its opposite in the same breath, so that something lands either way. Remember it when a quiz says flat white drinkers are sociable but need their own space. That fits everyone who has ever ordered a flat white, and most people who never have.

The coffee claim that did come from a real study is about black coffee and psychopaths. Christina Sagioglou and Tobias Greitemeyer at the University of Innsbruck asked nearly a thousand Americans online how much they liked a list of foods and drinks, coffee and radishes among them, and separately how much they liked bitter foods and drinks in general. Nobody tasted anything. Liking the bitter items on the list, coffee included, went with openness to experience and with none of the dark traits. The link they reported, strongest for everyday sadism and psychopathy, came from the general question, and the authors themselves wonder whether it caught the old stereotype that people who like bitter things are bitter people. The headlines went with black coffee anyway.

The ring on the desk

Rings are the bit I like best, because they outlast the cup. The physics was worked out in 1997 at the University of Chicago. The edge of a drying drop stays pinned in place, liquid flows outwards to replace what evaporates there, and it carries the coffee with it, which is why a ring is darker at the rim than in the middle. So a ring says a cup with a wet bottom stood there and nobody wiped up before it dried. Its size gives you the base of the cup. It does not give you a date, and a ring on bare wood can sit there for years.

One ring is an afternoon. Three overlapping rings in the same corner of a desk start to look like a habit, and the corner hints at which hand reaches for the mug, though plenty of left-handed people use a mouse with their right. I would write that down. I would not lean on it.

Sugar, stirrers and the clock

Two torn sugar sachets beside a cup might be two sugars, or one each for two people, and you settle that by counting cups, not by deciding the person has a sweet tooth and so a sweet nature. Surveys do find a small link between liking sweet things and being agreeable, far too small to read one person by. A wooden stirrer left in a takeaway cup says something got stirred in. A chewed one says somebody chewed it, and that is all it says.

Time is the most useful thing about a coffee, and the cup almost never carries it. A receipt does, and so does a clock on the wall. A second cup can too: two of the same drink on one desk, one gone cold, is a long morning. The case that taught me this turned on a receipt, a clock and a second cup that was not there.

One cup, eighty minutes

The Welcome (6 August) is a café table on a railway platform with nobody at it. On the table: one espresso cup on one saucer, a receipt, some coins and a folded banknote, a bouquet in paper, and a card lettered WELCOME HOME, ANNA. The far chair is still tucked under. The receipt was printed at 15:07, and the station clock on the pillar says nearly half past four.

On its own the cup tells you somebody had an espresso. Next to the receipt and the clock, that one cup has been made to last an hour and a quarter, which is how people wait when they keep thinking the next train will be the right one. One cup and a chair nobody pulled out say nobody joined them. The money left on the table says the wait ended on purpose, and the flowers left behind say Anna never came.

The first versions of that table were wrong. They had three espresso cups and three receipts spread through the afternoon, and once a cake. When I played them they read like two people having lunch, and nobody waiting for a train gets through three coffees anyway. People waiting buy one and nurse it. The fix was to take things away until a single cup was left, and let the receipt and the clock carry the time.

Move-In Ready (5 September) made the same point from the other side: a flat dressed for a listing, with two full mugs of tea on the coffee table as if just poured. Full mugs are suspicious, but a real person can pour a tea and wander off. The kettle settled it. Its cord was still in its tight factory coil, the plug connected to nothing. The mugs were a pose. The kettle had never boiled water, and that kind of history is hard to fake.

What I would let a cup tell me

Not much on its own. Where someone has been, if the cup carries a café's name. That a drink stood somewhere long enough to dry, if it left a ring. How long someone sat, if a receipt or a clock agrees. Almost never who they are. When a quiz says your order reveals your personality, look for the second sign, and usually there is none. Keeping what you see apart from what you conclude is most of thinking like Sherlock Holmes, and it works on whole rooms too. Today's case is a good place to try it.