If you know what that is, you're probably a fellow addict. Like every other drug culture this one has its own language, indecipherable to outsiders. Those of us in its grip look respectable in our working clothes, queuing for a shot, but it's easy to spot the brave soul going cold turkey: he or she is the one with the shakes, the headaches and the temper to drive away even the best of friends.
Best not to try giving up, really, and to take comfort in the knowledge that most of Britain is similarly addicted. We spend more than pounds 860 million a year on coffee, which some say makes it our favourite hot drink (actually we still drink more tea than coffee, but it's cheaper). The best evidence of our changing passions can be seen on High Streets across the nation, which are suddenly crowded with caffeine dealers.
Each outlet has its own following. To see beautiful men in sunglasses drinking espresso, go to an Italian-style chain like Caffe Nero. Hassled commuters fortify themselves at the station with a cappuccino from Costa Coffee, before boarding the 6.15 to Surbiton. Those who like a nice cake with their cup are best found at food chains like Pret A Manger, Patisserie Valerie and the Canadian Muffin Company. Exiled New Yorkers make their way to Coffee Republic, which takes its inspiration from America rather than Italy. So do discerning readers of the Independent on Sunday, since our Tried & Tested panel last year proclaimed the take-away cappuccino from Coffee Republic the best on the market.
All the chains we tested were committed to making a decent cup of coffee, with quality beans properly roasted, ground and brewed, and most of them have experienced rapid growth in the last couple of years. British people used to associate coffee houses with portly 18th-century gentlemen like Boswell and Dr Johnson, and coffee bars with hep cats like Cliff Richard and Tommy Steele. Until recently the only coffee available for most of us to take away was burger-bar stuff that tasted of petroleum (and had corrosive properties if it got onto your skin) or a mug of instant at the local greasy spoon, with UHT milk from one of those fiddly cartons. Now you're more likely to be able to get a good coffee while out shopping than a decent cup of tea.
The people who have ridden this wave of cultural change most profitably are Scott and Ally Svenson, the young couple who started the Seattle Coffee Company in 1995 and are now opening new stores at a rate of one a week. There were at least 56 when they last looked, but that figure will have risen again by the time this gets into print. Last month they sold the whole lot for pounds 49 million, which is not bad for three years' work.
The Svensons are natives of Seattle who came to Britain at the start of the Nineties. They missed the culture of their home town, the coffee capital of America, immediately. "I got into the country on Sunday, and on Monday Scott had to go to work," says Ally. "His office was on the other side of Hyde Park from where we were living. I said, `Great, I'll walk you to work and we can go grab a latte on the way'." Wishful thinking, it seems. "That's where our search began."
They enjoyed the authentic Italian coffee bars of Soho, where the espresso is the best outside Rome, but there was something missing. Ally calls it the Seattle attitude, but whatever does she mean? Seattle is one of the coldest places in America, so it's easy to see why the people who live there would become experts in making a cup of something hot and energising, but can there really be a common attitude in a city that has been home to both Bill Gates and Kurt Cobain? Ally's answer applies specifically to coffee: "The ability to go into a place and say, `Can I get an extra shot? Can I choose the kind of milk with that? What's your possibility on sizes?' Whenever we talked to people they agreed that it was so strange that Starbucks wasn't here."
That name was bound to crop up eventually, since the giant US Starbucks chain of coffee houses provided the direct inspiration for the Svenson empire. "We grew up with Starbucks, so what we came to know and love as gourmet coffee was down to them. They were the ones that did this first." Until 1986 there were seven Starbucks stores in Seattle, selling coffee beans and merchandise but no hot drinks. Then the company was bought by Howard Shulz, who set out to invent an American version of the espresso bars he had seen in Italy.
"America was not known for great coffee," says Scott Svenson. "There were mostly just corner coffee shops with mud that had been sitting in a pot on a stove for six hours. In Seattle they took the traditional espresso shot, which is an acquired taste and not palatable to a lot of people, and they introduced different variations, making it much more attractive to the mass market. And boom! Now everybody drinks coffee, whether it's buried in mocha or has whipped cream on top."
Starbucks became the market leader in an American coffee-shop explosion, and now has 1,500 sites across the States. It benefited from what the social commentator Faith Popcorn has identified as the search for a "third place", somewhere that isn't home or work, where people can meet and relax. With their tasteful furnishings, calming music and free newspapers, the new places were less threatening than alcohol bars, cheaper than restaurants, and the ideal environment in which to find a life partner. The phenomenon was validated when coffee bars provided settings for two of the great modern situation comedies, Frasier - which features the fictional Cafe Nervosa in Seattle - and Friends. Both are leisure-time porn, providing busy viewers with a tantalising glimpse of a world in which witty, attractive people spend all their time hanging out and drinking coffee.
As missionaries for this way of life, the Sven-sons look like perfect casting. Scott, who is 32, has the nervy grace of Frasier Crane's brother Niles with the angular face and dark, floppy hair of a young David Byrne, while the 30-year-old Ally could stand in as Rachel in Friends (except that she is pregnant with her second child). They are at their company's headquarters on an industrial estate near the family home in Fulham. "Day to day, on their way into work, our friends in Seattle are surrounded by snow-peaked mountains, water, big green trees," says Ally, nostalgically. "They leave their office at 5.30pm on Tuesday night and go water skiing. They go up to the slopes on Thursday night. They take time to enjoy life."
Scott warms to the theme. "Seattle attitude is about the ability to enjoy life's little rituals, to value that little respite in the day when you spend half an hour taking a break with friends." But he is also a single- minded businessman, who seems not to notice that he has changed the subject from Seattle in general to his own company's ideals. "To marry that with friendly service in a clean environment, and good quality gourmet coffee, so that it is an affordable luxury. It doesn't need to be a Mercedes or a Porsche, it can be a really nice cup of coffee."
The first Seattle Coffee Company store was housed in a listed building with no air conditioning in Covent Garden. The huge espresso machine generating heat in the back room made life difficult when it opened during the scorching summer of 1995. Ally quit her job in publishing to work in the store full- time, while Scott remained deputy chief executive of a public health-care company, working alongside his wife in the evenings and at weekends. "I was dropping her off at 5.30 in the morning and then going to work, before returning in the evening for the close. We wondered if we had made a big mistake."
By the end of that year they had opened another store on the second floor of a bookshop in Cambridge, and one at Canary Wharf in Lon-don's Docklands. Seattle was soon the name on a chain of stores, as it became obvious that Britain was developing its own coffee culture. There are many different reasons why this happened, and one of them is the usual British enthusiasm for whatever fad is sweeping the States. Another is our increasing sensitivity to all things European: we may not want the EU straightening out our bananas, but cheap travel to the Continent has exposed many more people to the cafe culture of cities like Paris and Rome. Global warming has helped: when the winters seem harsher we want something to warm us up, and when the summers seem sunnier we can sit outside and pretend to be in St Mark's Square. These days many people are working longer hours, so it helps to have a little boost. There's even a name - "the jitterati" - for those computer-bound workers who rely on coffee to keep them up through the night, meeting deadlines.
The lingo you need to master to order a drink in one of the new coffee bars makes regular customers feel that they're in on a secret - a sense of belonging that every marketing department knows to be lucrative. So it has proved over the last five years, during which time the annual amount of money the British spend on drinking coffee has risen by pounds 300 million.
When fashion begins to make that sort of financial impact, the multi- nationals take note. Nobody can be surprised then that the new culture is being embraced by Nescafe, the company which used the sexy yuppie Gold Blend couple to push its instant product upmarket during the Eighties. The first two Nescafe Coffee House sites opened as an experiment last year, at shopping centres in Leeds and Kingston, Surrey. The company now plans a national chain, and says it wants "penetration like McDonald's". Nescafe's menu acknowledges that coffee drinkers have developed new tastes, but it plans to make mocha and latte with instant coffee.
That very idea would horrify any self-respecting barista, as those who serve in the new coffee bars are called after the Italian fashion (to pronounce it properly, imagine you are Sophia Loren rather than Rumpole of the Bailey). At the Seattle Coffee Company they must go through an intensive three-day training course. "You spend a lot of money on the coffee and the roasting, then you might get some barista who's just not paying attention and they can ruin it," says Scott Svenson. "The difference between preparing it properly or not is night and day."
Before they even get to the training, would-be baristas have to pass the audition. The selection process involves role play and in some cases the wearing of pink fluffy rabbit ears. "The way people react is very important - we want to see if they are team players, or if they are going to go into a shell? You can teach them all the coffee stuff but are they people-people?"
Suddenly Scott sounds like he's running Dis-neyland. Does he know just how grumpy some of us can be in the morning, and how much it gets up our noses to be greeted by a smarmy young thing with a fixed smile who hopes we have a nice day?
"Until I spent that first year working behind the bar I had no idea what level of responsibility you have as a barista in making or breaking people's day," says Ally. "You might be giving somebody a coffee on their way to the most important job interview of their life, or their first coffee after their wife has just given birth." Seattle differs from its rivals in seeing baristas as the most important part of the whole operation, she stresses, which makes me wonder why they only get paid pounds 4 an hour, a standard rate in the industry. For that money, how good are the workers going to be, and how long will they stay?
Then Ally says something that reminds me there is a cultural gap between us wider than the Atlantic. "From time to time we ask people back home in Seattle what they love about their local cafe, and they say, `They know me, they recognise me, they've been everything with me - they're the ones who were there when I broke up with so-and-so'."
Enough schmaltz, already. Let's get back to the coffee.
THE FIRST THING you need to know is that the coffee bean is actually a seed. Two of them are contained in each pod, which looks like a green berry when it is growing on the tree. When the fruit is ripe it turns red, and is known as a cherry. There are dozens of different beans - and as many different ways of growing and harvesting them - but let us take as our example a good quality South American bean, grown on a small plantation for the gourmet coffee market. The cherries are picked by hand, because they do not ripen all at once and some may not be ready. On the huge plantations that make coffee for the mass market, the picking is done by machine.
Next the cherries fill three-quarters of a steel or concrete fermentation tank, which is topped up with water to soften the flesh around the seeds. The flesh is then separated off in a rotating drum, and sometimes used in organic farming. The seeds, still bound together in pairs by a skin known as the parchment, are then dried - either on terraces in the sunshine or in a drying room where the temperature and humidity are closely controlled. The parchment will not be removed until the seeds are ready to be shipped out. When that happens they are individually sorted, a crucial moment in the life of a young coffee bean. Each one goes into a tube which has a light cell on either side, measuring its density and dryness. Any that do not measure up to the standards required are ejected from the tube by a blast of air. Those that make it are bagged up, ready to go.
Some are destined for a grim industrial estate in Canning Town, East London. Behind the shuttered doors are the premises of Torz & Macatonia, suppliers of gourmet beans to smart London restaurants like the Bluebird and Le Caprice, as well as the Seattle Coffee Company. Jeremy Torz, who co-founded the company after pining for the beans he had tasted in San Francisco, stands by a sack from Columbia which weighs 70 kilos and has cost him around pounds 400. Coffee prices are rising fast at the moment because of freak weather conditions associated with El Nino, but there is still money to be made: by the time the beans have been roasted by Torz & Macatonia, despatched to a Seattle store, ground, brewed in an espresso machine and served in a bewildering variety of ways, they will have provided the basis for more than 4,000 cups of coffee, generating up to pounds 6,000.
The secret is in the roasting, a process in which the beans are tumbled over heat in a drum filled with hot air. The giant coffee companies can do this in 90 seconds. Torz & Macatonia take up to 16 minutes, and the juggling of time and temperature creates the darker roast associated with the new coffee houses. Jeremy Torz compares the process to alchemy. "It is 80 per cent science and 20 per cent witchcraft. It's the witchcraft that sometimes buggers it up."
THE INEVITABLE happened. Starbucks took note of what was happening in Britain, and decided to enter the market. Scott and Ally Svenson could have started a coffee war, but instead David sold out to Goliath. Once the other investors had been paid, the founders ended up with pounds 14 million and jobs for themselves and their team with Starbucks.
The irony is that this couple who set up a coffee house because they wanted somewhere to relax have been too busy running the company to take advantage of it. "It's something that Scott and I struggle with," says Ally, clearly embarrassed. "It's our character, full stop. We fit into that category of over-achiever where you just want to kick 'em in the butt and say `chill out, kick back'."
Then she says it again. "`To be honest with you, we've just had our first real weekend off in as long as we can remember. We went to the zoo and we saw a movie. If you talk to anybody that's starting a business it is 24 hours a day and seven days a week. It is our life. I'm not complaining, because the business we've created comes from a hobby. Nobody should feel sorry for us."
Any sympathy I have for this wealthy workaholic evaporates in the queue for a latte at the local branch of Seattle. The staff, who have recently been changed en masse, are comically inept. The first barista gets the order wrong, the second knows it but fails to correct him and the third in line serves the two people behind me before remembering my shots of espresso growing cold on the side. All three are sullen to the point of rudeness. The warning on the side of the cup - "this drink is hot!" - is wishful thinking. It is over-priced froth. As the head barista gives a roasting to his most inept underling, and the others sulk rather than serve, I can't help thinking that there are some ways of working to which British people still have an instinctive resistance. "Thanks," I say, although no-one is listening. "Have a nice day."
Assuming that you can already tell the difference between a cappuccino and an espresso, there are some terms to learn if you don't want to feel intimidated in one of the new-style coffee houses. Most serve their coffees in three sizes - short, tall and grande - although the actual amount you get will differ wildly.
Americano: espresso with steamed water.
Con panna: espresso that's marked with whipped cream.
Dry: served with extra foam.
Harmless: skinny and no fun (see below).
Latte: espresso shot, steamed milk, foamed milk.
Macchiato: espresso marked with foamed milk.
Mocha: espresso, chocolate syrup, steamed milk and whipped cream.
No fun: decaffeinated coffee.
Ristretto: smaller, more intense espresso.
Skinny: skimmed milk.
Wet: extra steamed milk.
Wild: extra whipped cream.
With Wings: to take away.