What is the difference between steam and pump espresso machines?
Pressure is the primary variable that distinguishes espresso from other methods of brewing coffee. All types of espresso machines must generate pressure, and there are two methods that machines use to do so. Pump espresso machines and steam espresso machines fundamentally differ in how they generate the pressure that’s required to brew espresso.
The resulting difference in the amount of pressure and temperature created impacts the flavor and quality of the espresso shot. The pump espresso machine creates a rich shot with the signature crema, while the steam machine produces a shot that is more “espresso-like” – it’s delicious and satisfying, but not quite the same as a shot from a pump machine.
Let’s explore the differences in more detail.
In This Guide:
How Steam Espresso Makers Work
Steam espresso machines rely on the same science as Angelo Moriondo did when he patented the first espresso machine in 1884. Although these machines have been refined over the past 140 years, they still generate pressure by heating water until it becomes steam.
The Moka Pot is a good example of how steam espresso makers work:
- Water is manually poured into a boiler or other chamber.
- The water chamber is heated until sufficient steam is generated.
- The steam is channeled through coffee grounds.
- “Espresso” is brewed into a third chamber (or cup).
Other steam espresso machines orient the main components (i.e. water chamber, heating element, ground chamber, brewing chamber) differently. However the components are oriented, however, the process of brewing remains essentially the same.
In addition to the espresso brewing components, some steam espresso machines also have a steam wand for frothing milk. This is an easy feature to add, since water is already sufficiently heated to produce steam.
The Moka Pot (Amazon affiliate link) is far from the only steam espresso maker, but it’s the most well-known and showcases the fundamentals of these machines well.
Advantages of Steam Espresso Machines
Affordable Espresso Makers
Steam espresso machines are the more affordable of the two types. Because they’re simpler systems, they can be built at lower costs and last longer. With little care other than cleaning, some of these machines can last for years.
Anyone who’s purchased a Moka Pot can appreciate how inexpensive and durable steam espresso makers are. Moka Pots can be had for less than what lunch at a cafe might cost, and they usually can be found in a kitchen cupboard long after they’re bought. Even fancier steam machines usually cost not much more than a standard drip coffee maker.
Cons of Steam Espresso Machines
Compared to pump espresso machines, steam machines have three significant drawbacks. All of them stem from the reliance on steam.
Overheating Causes Bitterness
First, most steam espresso machines require near-continual heat in order to sustain the necessary pressure. Continually heating easily overheats the entire espresso maker, burning yourself if you touch it and coffee grounds as they brew. Excessive bitterness is a sign that coffee (of any kind) may have been brewed at too high a temperature.
In one video on brewing with the Moka Pot, James Hoffman spends a lot of time discussing ways that the espresso maker can be kept from overheating. Much of the same can be said for other steam espresso machines — your espresso will be vastly improved if you can keep the espresso cool.
Low Pressure Doesn’t Create Crema
Second, steam espresso machines don’t generate as much pressure as pump machines. Most steam machines produce 1-3 bars of pressure, whereas modern espresso is normally pulled around 8-9 bars. The lower pressure changes the brew significantly — such that many people don’t consider the brew from these machines to be true espresso.
The effects of the lower pressure are visually noticeable in the lack of crema that these machines produce. They can’t create the minuscule aeration that results in crema floating on top of an espresso shot. (Some models have specialized valves that create crema-like aeration.)
Taste is also diminished, as the lower pressure isn’t able to extract as well. Espresso won’t be as flavorful, bright or vivacious when made with a steam machine.
Wait Times While Pressure Rebuilds.
Third, steam espresso makers that make a single cup at a time frequently must rebuild pressure between cups. When you’re making more than one cup of espresso, this causes a delay. Not only does the delay require patience, but it also is time when the already-made drinks are cooling off and the machine is getting hotter.
How Pump Espresso Machines Work
Pump espresso machines were developed largely to address the temperature issues that steam machines present, and better extraction was a byproduct of this innovation. The very first pump machines were manually operated by raising and lowering a lever, but today’s machines usually have an internal pump.
The internal pump has a thermo-blocking system that prevents the water from becoming excessively hot. The water is passed over a heating element that quickly generates pressurized steam, as opposed to being constantly heated by an element that generates lower-pressure steam. The pump design therefore provides more pressure and greater temperature stability.
Most pump espresso machines come with a steam wand, which may be operated by the same pump system or a separate system. Having a separate system is useful in cafe settings, as it allows baristas to simultaneously pull shots and steam milk.
Advantages of Pump Espresso Machines
The pressure that pump espresso machines easily reaches 8-9 bars, which is what modern espresso shots are pulled at. This pressure provides aeration to create crema when freshly roasted coffee is used for espresso, and the pressure fully extracts grounds. The result is the vibrant, flavorful espresso shot that has a heart, body and crema.
Multiple Levels of Convenience
Pump espresso machines offer a range of experiences, varying from pretty hands-on to completely hands-off. Three categories of machines are broken down according to how much work is involved:
- Semi-automatic espresso machines require you to grind, dose and tamp, and you also control the volume of water used. The machine only provides the pressurized water.
- With a semi-automatic machine, you have almost complete control over extraction but must prepare and watch each shot.
Examples of semi-automatic espresso machines on Amazon.
Examples of semi-automatic espresso machines on 1st in Coffee. - Automatic espresso machines require you to grind, dose and tamp. The machine controls the water volume and pressure, extracting according to settings that you can select.
- Automatic machines still give you control over multiple variables, but you don’t have to watch the shot. This allows you to prep another shot or steam milk while the espresso is pulling. It also lets you focus solely on preparing the grounds since the water is controlled.
Examples of automatic espresso machines on Amazon. - Super-automatic machines grind, dose, tamp, and control all aspects of the water. Feature-rich ones can even steam and pour milk for you.
- These machines are completely hands-off, as you only need to press a button. Have a delicious espresso beverage without any effort.
Examples of super-automatic espresso machines on Amazon.
Super-automatic espresso machines on 1st in Coffee.
Cons of Pump Espresso Machines
More Involved Maintenance
The pump in these machines adds mechanical complexity, and it will eventually wear out. How long the pump lasts depends on the build quality of a machine, but you should be prepared to repair or replace it eventually. Which solution is best likely depends on the cost of the machine.
Models Can Be Expensive
All pump espresso machines cost more than steam machines of comparable quality. Feature-rich automatic machines can be downright expensive, and are primarily found in cafes.
Are Pump Espresso Machines Better?
Pump espresso machines make better espresso, but they require a larger financial investment — both upfront and when the pump requires service. Steam espresso machines make delicious espresso-like coffee without a lot of cost.
If you don’t have an espresso machine, a steam machine might be wise to start with. You can see how much you actually use the machine, and then upgrade to a pump machine when you determine that you will regularly use it.
If you already have an espresso machine or know that you’ll use one consistently, a pump machine is a better choice. You can get true espresso, make espresso/milk beverages, and choose how much you want to be involved in pulling shots.
In either case, an espresso maker is a worthwhile investment if you like strong, flavorful coffee. If you currently only drink brewed coffee, either type of machine will make coffee that’s different from what you currently drink.
Scott M. Brodie has over 20 years of professional experience working in coffee shops and writing about coffee (including selling superautomatic machines). When not writing, he can usually be found roasting a new African single origin or composing a fictional work.