Automatic Espresso Machines - A Primer

Starting the morning without a fresh cup of steaming coffee can be a real challenge for some of us. I, for one, can barely start the morning without a jolt of caffeine. But if you, like me, are fussy about coffee then not just any cup will do. I am afraid to say that powdered instant coffee just does not taste right to me. So that leaves coffee made from ground beans.

There are two main approaches to making coffee. The first is the drip, or filter method. This works on the simple principle of allowing water that is almost boiling to drip through coffee, picking up flavor as it goes. A related and closely linked method is to steep coffee grinds in hot water before filtering or straining it. These variations are most popular in America and Britain.

Yet they have in recent years been supplanted to some extent by espresso machines. The main difference between them is that espresso is produced by forcing hot water through beans at high pressure, typically about 6 to 8 bar (one bar is the equivalent of the pressure the atmosphere exerts at sea level). This allows the water to be much hotter and it produces a stronger, more bitter-tasting coffee. For some time this was best produced by an experienced operator using a complicated manual machine. A trained operator was needed to balance temperature and pressure through a complicated set of valves and pipes. More recently this process has been largely automated with machines and pumps now controlling pressure and temperature to produce cups of coffee that are consistent in quality, temperature and volume.

These machines come in various forms. Some will take beans, grind them, measure out the correct quantity of coffee grinds and produce a cup of coffee. All they need is clean water, electric power and, naturally, a steady supply of coffee beans. They then produce coffee at the press of a button. Semi-automatic machines require more human intervention as the operator has to grind the beans separately and measure them into a receptacle that is then placed in the machine. These sorts of machines are commonly seen in many big coffee shop chains.

At the next end of the scale is the completely manual espresso machine. Although these are still in use in many parts of the world, they are seldom found in private homes. When they are then they represent a sure sign that the homeowner is a real espresso aficionado.