Italians know how to express it so well: A revolution is brewing in the way the British make and drink coffee, writes Chris Long

THE Italians are coming, the Italians are coming] Take, for example, the Costa Brothers Coffee Company. It has just opened its second coffee boutique at East Croydon railway station. Commuters can now experience what is probably the best way to drink coffee while waiting to insert themselves into the 8.32 to Victoria. And there are more boutiques on the way, at the Thames Citylink station and Edinburgh airport, bringing the number to 30.

In addition, the kitchen goods manufacturer De'Longhi recently launched its espresso machines here. In the past six months it has sold more than 3,200 units and now sells espresso machines to the masses via the high street retailer Comet.

Small, dark and poisonously strong, and as steeped in arcane rituals as the British cuppa, Italian espresso is making a comeback in the UK.

Why a comeback? In the Fifties, the trend was expresso bars, where kids hung out before hanging out was invented, doing their James Dean and Marlon Brando impersonations. The film Expresso Bongo could not have helped much. The image of Cliff Richard strutting around a cafe with bongos is likely to have put the cause of espresso drinking back 20 years. Until now.

Espresso, the quintessential Italian coffee, is fast becoming the drink of choice for those with a discerning palate. And in the Nineties, it is spelt with an 's' - the word means 'expressed' in Italian.

Coffee drinking had been going on for a thousand years without much happening in the way of new technology, but the early 1800s saw a rash of coffee-maker designs. Basically they were all variations on a theme in which, one way or another, boiling water or steam was passed through freshly ground coffee.

That era saw the invention of such exotic devices as the percolator and the vacuum balloon coffee machine, and the only slightly less exotic, but infinitely more successful, drip pot.

Louis Bernard Rabaut invented the espresso machine in 1822. Its principle was simple: an aluminium pot in two halves, with water in the bottom and an empty chamber at the top. The two sections were separated by a small carrier filled with finely ground coffee, then the water in the bottom was heated to boiling point. The steam forced its way through the coffee into the empty chamber above and condensed as espresso.

This is also known as a mocha coffee pot and is the standard device for home espresso makers. The same principle is used in low-end espresso machines, in which an electric element heats water in a boiler and the steam (at a slightly higher pressure) is forced through the coffee.

But the Rolls-Royce of espresso machines is the pump machine. In 1946, Achille Gaggia revolutionised espresso drinking. He realised that steam or boiling water going through the finely ground coffee burnt it, marring the taste. So he devised a system where hot, but not boiling, water was pumped through the coffee.

The trick is mainly in the water temperature, although there are other factors. Fresh water at 95C is pumped through the firmly packed coffee at a pressure of anything up to 15 bar (about 15 atmospheres). It is important the coffee be tamped down in its holder to give the pressurised water some resistance.

The coffee technicians at De'

Longhi say the coffee in the cup (straight from the machine) should be around 85C, and recommend warming the cup first. The cup - a demitasse, preferably ceramic or porcelain - is de rigueur, because you only get about 35ml of fluid in one shot of true Italian espresso. The experts add that coffee for pump espresso must be ground to five or six microns, whereas a mocha unit needs nine to 10 microns: very fine and fine.

The most surprising fact about espresso coffee, says the Coffee Science Information Centre, is that it has less caffeine than filter coffee. This is down to the way the drink is made. Because the whole operation takes less than 30 seconds and you are producing 35ml or so of fluid, less caffeine is drawn out.

There are two main components in coffee: soluble and insoluble substances. The former are the caffeine, sugar and proteins, the latter the oils and colloids. The oils supply the aroma and ultimately the taste, while the colloids help to produce the distinctive light brown 'crema' on the top of an espresso which, according to the Italians, seals in the flavour.

The insoluble parts of the coffee are flushed through first, leaving some of the solubles - including the caffeine - behind. Thus, in a small cup of espresso there are about 70mg of caffeine compared to about 85 to 100mg in a cup of instant. Although it does not take too much imagination to spot that a mug of espresso could contain an awful lot more.

Cappuccino is a derivative of espresso: frothed milk is spooned on to the top of a mixture of expresso and milk. The milk is made frothy by pumping steam through it, usually from a device built in to the pump unit.

The rising number of coffee boutiques shows how public tastes are changing. It seems you cannot arrive at a British Rail terminus without being confronted by a group of people standing around, staring into the middle distance, drinking from small cups.

We are now being targeted by the Italians, who are keen to sell us their culture. So much so that De'Longhi is making a push into Britain with a new range of espresso machines.

So, if you are one of those people who, when serving instant coffee to guests, goes into the kitchen and imitates a coffee machine by making slurping noises, it may be a good idea to investigate another technology.

(Photograph omitted)