How Espresso Machines Work

The more you know about how espresso machines work, the easier it will be when you start searching for one for your home.

In recent years, espresso makers have become more and more popular in the homes of people who enjoy special coffees. Since they have become so popular, there are now many different models and styles that you can choose from today.

Actually, the espresso maker is quite a simple appliance and it is made to heat up water to somewhere between 130 - 140° F, and then it pushes the water through coffee that is ground at between 8-10 bars of pressure.

There are a variety of different heating methods used in espresso machines and there are different pressure methods that are available as well.

Various Heating Methods

When it comes to espresso makers, there are a variety of different heating methods that you can choose from. The following are some of the heating methods that you'll be able to choose from when you are picking out your own espresso machine.

Heating Method #1 - Boiler or Heat Shedding Group
This system is actually the oldest system of heating the water in an espresso machine. The water in the machine is taken right from the steam boiler and at this point it is about 250° F. Before the water gets to the coffee, it gets down to the right temperature for brewing.

This type of heating method is not always the most accurate and you can end up with a final brew temperature that is too high or too low. In fact, if you want to brew more than a few shots, you'll probably have to turn off the machine for awhile to get the temperature down.

Heating Method #2 - Heat Exchanger
Most contemporary machines that are commercial or large home machines usually use the heat exchange system to heat the water. This heat exchanger is located on the inside of the boiler and you can adjust the average temperature by either raising or lowering the temperature of the steam boiler.

This is not a precise system of getting the right temperature; however, usually a good machine with this heating method will get the temperature within a couple degrees. If this type of a machine is idle for awhile, the exchange can overheat, which can lead to the water getting too hot.

The main advantage of this type of a machine is that it can make shots and steam milk all at the same time.

Heating Method #3 - Single Boiler
Many small home espresso machines have a single boiler that has no heat exchanger. There are two different thermostats used in these machines.

There are several different types of thermostats that can be used, and the best machines use either electronic thermostats or vapor pressure thermostats to make sure that the water is the right temperature.

Heating Method #4 - Double Boiler
If you only have a single boiler, you cannot pull shots and steam at the same time; however, you can with a double boiler. Some of these machines have been perfected so they can deliver stable temperatures as well.

These espresso machines are the easiest to set to the temperature you prefer. While they used to be only available for commercial use, they are now available for homes as well, although they are rather pricey.

Different Pressure Methods Available

There is also a variety of different available pressure methods used in different espresso makers. Some of the methods include rotary pumps, spring levers, and vibratory pumps.

Rotary Pumps
Many different espresso machines that are used for commercial use contain rotary pumps. This type of a pump can actually provide plenty of flow at 9 bar, which is enough to serve a variety of people at the same time.

You can adjust the pressure on these machines and while they are not totally free of vibration, they are fairly quiet and smooth. Most people will find that this type of a machine is too much for home use, but it definitely works well in a commercial setting.

Spring Levers
Spring levers are the oldest type of pressure method used in these machines; in fact, this type of system dates all the way back to the 1940's. In order to pressurize the water in this machine, a special piston and cylinder system is used.

The operator actually applies the pressure in many of these machines designed for home use. However, it can be difficult to accurately and smoothly apply the pressure that is needed. While this type of a machine will reduce the amount of cream, it will make the shot more transparent and more pure as well.

Vibratory Pumps
When it comes to espresso machines for home use, the vibratory pump is the most popular. This is a device for making espresso that is small and cheap, and perfect for making this drink at home.

A vibratory machine has more vibration than other types of pumps and this helps to produce more crema.

Other Machine Factors
Of course there are other factors to consider when you are looking at espresso machines as well. While some of these factors do not really have anything to do with the quality of coffee, they do have to do with the way your machine will look.

You can purchase machines that look super sharp and pay more dollars for the looks but that doesn't give you great tasting espresso. There are other types of machines that have components that are designed to last a lifetime, and if you plan on using your espresso maker on a regular basis, it may be worth your while to pay a bit more for a better and more durable machine.