subject: How Espresso Machines Work [print this page] Two hundred three degrees FahrenheitTwo hundred three degrees Fahrenheit. Nope, it's not the name of the next summer blockbuster, though it is something that is loved all around the world, something that many people cannot do without. Two hundred three degrees Fahrenheit is the perfect temperature for a cup of coffee. And how is this number derived? Not a clue. But those who know are the manufacturers of espresso machines from Canada to Columbia.
That is how hot the water gets before the little electromagnetic switch in the inner workings of the machine tells the heater that the job is done. So how do espresso machines work anyway? First of all they have to look cool - that is an unspoken but important rule. After that it is a simple process that involves several elements. The espresso machine is made up of three major components: a water reservoir, a coffee grounds filter and container, and a steam wand.
The water from the reservoir is pumped into the boiler where it can be heated. The power button allows the electricity to run through a thermostat and into a coiled heating element inside the boiler. This is where the magic 203 degrees Fahrenheit is achieved, just below the boiling point of water. If the water were allowed to boil it would result in bitter, burned coffee. There aren't many people who enjoy the smell or taste of burned coffee.
Once the right temperature has been reached, a microcircuit is broken which interrupts the flow of electricity to the element. At this point, the electricity is diverted by the thermostat to a control panel that usually causes a light to signal that the water is ready. Making sure that the filter is in place and the cup placed beneath, the user pushes the button and the pump kicks in a second time, creating a piston pressure equal to two hundred twenty pounds per square inch - not quite the same pressure as an elephant sitting on you, but close.
The almost boiling water is pushed through a lower boiler, through the valve, and out through the filter and into the cup. And thus, your espresso is born, steaming hot, just the way you like it. The stem wand attachment is used to whip the milk by injecting steam into the liquid, and you get the frothy feel of real Italian espresso.
So, the next time you fill up the water, slot in the filter and press 'go,' you know a little bit about the magic of what goes on behind the shiny, sleek exterior of your super-cool looking espresso machine.
