Espresso Machines in general are very expensive coffee brewing machines, easily ranging up to $1,000 US (2006 prices.) The coffee is brewed by water driving at pressure through the coffee.
Steam-driven machines are cheaper. Next best are pump machines, but espresso zealots will often settle for nothing less than a piston espresso machine, the most expensive.
An Espresso Machine requires dedicated counter space both for the machine and the accoutrements, and of course, for display — the sleek “look” of an espresso machine is part of the appeal. For this reason, it’s generally recommended not to give an Espresso Machine to anyone unless you are absolutely sure it will be used — too many end up languishing at the back of cupboards.
You can get also small personal ones now, small enough to pop into a briefcase or handbag so you can make espresso wherever you have a few minutes and an electrical outlet.
In reading about Espresso Machines, you will often see the term “bars” used. Bars in this context is a unit for measuring atmospheric pressure. 1 bar = 14.504 pound-force per
square inch (psi) / 100,000 Pascals. A bar doesn’t exactly equal the unit of measure called an “atmosphere”, but it’s close enough for kitchen purposes that the word “atmosphere” is often used instead of bar. A standard pressure for Espresso Machines is often given as 15 bars / 15 atmospheres / 220 psi. 15 bars is the minimum needed to produce the kind of creamy, rich espresso that you can buy in coffee shops.
Though a few models take only pre-packed small pouches or pods, so that your purchase becomes a prayer that the maker of these stays around, most machines let you spoon ground coffee into a filter basket. Some machines have an attached grinder and grind the coffee beans for you.
Most machines have a mechanism for frothing milk as well for cappuccino. This is almost always a wand, which is almost always on the right-hand side of the machine. Some wands are fixed into place, some will swivel horizontally and vertically. Steam comes out of these when you indicate that you want it. You put a pitcher of milk beneath the wand, and raise the pitcher so that the tip of the wand is in the milk. A few machines, though, have compartments that the wand goes into that you put the milk into.
The filters on pump machines have handles on them. You put the coffee in, level the coffee off with a finger, and press it down with a “tamper” often provided usually made of aluminum or plastic. This is necessary to ensure that the coffee grounds are packed in evenly. If there’s a lot of open space, the water will choose to go through there, bypassing most of the coffee. Experts advise to press down with about 30 pounds of pressure (it’s not mentioned how exactly you measure this on your kitchen counter.)
Pump Espresso Machines can cost hundreds of dollars, but can be a good buy for those who buy espresso out regularly, and want to save money by switching to home consumption.
They have a reservoir that you put your water into, where it is heated. The pump does this by pulling the water out of the reservoir, and cycling it from the reservoir through a heating chamber and back into the reservoir. The machine will indicate when the water is hot enough to use. At this point, you push a button to tell it to make the coffee. The pump then pressurizes the water to 15 bars, when forces the water out through the coffee in the filter basket, and out of the spout into the waiting cup. Some of the pump models have very noisy pumps, though.
Many Italians, though, just use stove top ones at home. The water goes into the bottom of stove-top espresso coffee pot. You rest a filter on the top of this base, and put the coffee in the filter. This rests just above the water. Then, you screw the top of very tightly, and put the coffee pot on a burner on the stove. As the water in the base boils, pressure forces water up through the coffee, and then out a pipe into a waiting jug or cup. The problem with these is that the temperature required for this to work can be too high, making the coffee taste burnt and bitter.
Moka and Neapolitan Flip Coffee Maker are sometimes referred to as Espresso machines, because they make “strong” coffee (compared to drip-coffee in the English speaking world), but they aren’t. For a coffee-making device to be an Espresso Machine, the water must be driven through the ground coffee, not drip through it.
Some Espresso Machine machines require a long warm-up time.
With any Espresso Machine, you need to learn the right technique for your taste. If you use too little coffee, or pack it down too weakly, the espresso can be watery. If you use too much coffee, or packed it in too tightly, the espresso can be bitter.
You also have to learn what is the right amount of pressure, and to release the water for the right amount of time. Most of the bitter elements in a cup of espresso come out at the end of the extraction.
Espresso cups are generally warmed before pouring coffee into them. Some machines have a cup warmer, usually a plate at the top of the machine where you put the cups, but some plates don’t get warm enough to really make any difference, or can be so small you can barely fit two cups on it.
In Italian, the espresso-machine operator is called a “barista” because he works at a “bar.”