Choosing the right espresso machine can be tricky – so here’s our guide to everything you need to consider, including prices, features and quality.

Three design options

There are three main types of domestic espresso machine out there:

Single boiler (SB)

One boiler which provides hot water for brewing espresso and steam for milk – but cannot do both at the same time. As you switch from espresso to steam, the boiler needs to increase in temperature, and vice versa.

Single boiler machines traditionally come with internal water reservoirs, with no mains water connection option. These machines are the cheapest models you can get that are capable of pulling great espresso. The single boiler means that it takes time to learn how to pull the perfect shot. However, if you’re willing to experiment, they can be a great option, with low outlay.

Pros

  • Low cost; delivers high quality for less.

Cons

  • Lack of temperature stability can be inconvenient and can take some time to master. A way around this is to ‘temperature surf’ (this involves learning how the thermostat behaves and precisely timing when you pull a shot – see this forum thread for more information).
  • No frills design: unable to brew espresso and steam milk at the same time.
  • No automatic boiler refill.
  • Not ideal for making large quantities of milk drinks because the water reservoir will need to be refilled frequently. 

Heat Exchanger (HX)

One boiler that heats water for brewing espresso and hot water/steam – and do allow you to use both functions simultaneously.

The water in the boiler is superheated to create steam. When a shot of espresso is pulled, that water comes from a coiled HX pipe which sits within the boiler. Additional cold water has been pulled into the pipe so that its temperature is cooler than the main section of the boiler. This design results in two separate temperatures to meet the demands of brewing and steaming at the same time.

Most HXs offer gauges showing boiler and/or pump pressure, and many models offer the ability to adjust these parameters. HXs come with a mix of connection options (model dependent) including internal reservoir, mains water connection or both.

They are more expensive than single boilers, but provide good value due to their higher grade build, quality components (often commercial grade), convenience and most importantly - reliable temperature control.

Pros

  • Higher quality piece of equipment.
  • Improved temperature stability (less experimenting is needed to pull a great shot).
  • Water source options.
  • The ability to prepare espresso and steam milk simultaneously.
  • Automatic boiler refill.
  • Perfect if you drink milk-based coffees (latte/cappuccino/flat white).

Cons

  • Higher cost than single boiler machines.
  • Larger in size.
  • Not as accurate as dual boiler machines for temperature control; requires techniques such as ‘cooling flushes’ to get the right brewing temperature – so slightly less convenient than a dual boiler machine.

Dual boiler (DB)

Two boilers - one dedicated to providing hot water for brewing espresso and one for hot water/steam. This means you can prepare espresso and steam milk simultaneously.

Many DB machines also come with a ‘PID’. This is a digital temperature controller that allows you to accurately change the temperature of espresso extraction to suit different coffees.

The build quality of these machines is usually very high, with excellent design and high-grade components. DBs offer ultimate convenience and are feature-rich, leaving the user able to control and adjust as they please. They come with a mix of connection options (model dependent) including internal reservoir, mains water connection or both. They are typically at the top end in terms of price, due to their multiple boilers and high-grade components.

Pros

  • High build quality and components.
  • Extremely solid temperature stability.
  • Water connection options.
  • Ability to prepare espresso and steam milk simultaneously.
  • Perfect if you drink milk-based coffees (latte/cappuccino/flat white).
  • Easier to use than an HX and Single boiler - they provide maximum control.

Cons

  • Higher cost.
  • Larger in size than single boiler machines.

      Other features to consider

      Across all types of machine there are a number of other key features that may contribute to your final decision.

      Manual (E61) group heads
      These use a lever to allow water to enter the group (offering pre-infusion of the coffee) before activating the pump and delivering your shot as normal. Pre-infusion is where water is in contact with the coffee for a short period of time at a very low pressure before that pressure increases and full extraction starts. It allows subtle flavours to shine through, and also is more forgiving if your tamping isn’t 100% perfect.

      Manual (Traditional Lever) group heads
      Traditional Lever machines have a large handle protruding from the top of the group head. Pulling down on the lever allows water to fill the group, and releasing it engages a piston which forces that water down through the coffee, delivering your shot as normal. Lever machines offer both pre-infusion and post-infusion. This means a gradual ramp UP in pressure at the beginning of the shot, and a gradual ramp DOWN in pressure towards the end of the shot, allowing different flavours to develop. Shots from a lever often taste very unique.

      Semi Auto (ON/OFF Brew switch)
      Semi automatic machines have a switch/button on the front panel that starts or stops the extraction process. The Rancilio Silvia is an example of this type of machine.

      Automatic (programmed keypad)
      Some machines have an automatic extraction process. This means that once you’ve done your perfect tamp, and inserted the portafilter into the group-head, you only need to select the correct preset button to pull the type of shot you want (single or double).

      PID Temperature Controller
      Shows you the temperature of the boiler and allows you to control that temperature digitally.

      Adjustable brewing pressure
      Allows you to adjust it to suit your coffee.

      Adjustable steam temperature
      Allows you to adjust it to suit your milk/steaming technique for good microfoam.

      Boiler pressure gauge
      Displays the pressure of the steam boiler.

      Brewing pressure gauge
      Displays the pressure at which your shot is being extracted.

       

      Pump type

      Rotary pumps

      Used in commercial and high-end domestic machines such as the Rocket R58. Rotary pumps offer a more stable pressure for extraction. They are quieter and adjustable. They do cost more to replace, but they also have a longer lifespan.

      Vibratory (or Vibe) pumps

      Commonplace in most low- to mid-range domestic machines. Vibratory pumps are the noisier of the two pump types, but can only be heard when water needs to be pumped into the boiler. They do need replacing more often than rotary pumps, but are reasonably priced (under £40).

       

      Price

      In the world of espresso machines, the more you pay the easier it gets to pull a great shot, because the lower end machines require more of an understanding of temperature surfing techniques.

      This seems a little unfair, as those with smaller budgets face a bigger battle / learning curve. However, some people really enjoy learning to get to grips with the less expensive single boiler machines.

      Low end

      Single boiler machines are the cheapest as they have only one boiler which dramatically lowers the cost of manufacturing. You can buy single boiler machines for as little as £80 in high street department stores, but don’t be fooled. These machines are not capable of delivering consistent and stable temperature levels, which need to be achieved for great espresso. The lowest cost SB that can actually produce decent espresso is around £370 (The Rancilio Silvia), with prices going up to around the £600 mark.

      Middle

      HX machines can be bought for between £600 – £1200, depending on brand, build and additional features. They tend to look more impressive and elegantly designed than single boilers. Many people opt for HX machines, as they offer virtually all that dual boilers provide including better build quality / components, temperature stability, etc - without the higher cost. Ideal for espresso and milk based drinks – but they do not offer quite the level of control over steam and brewing temperature, that the dual boilers do.

      High end

      Lastly, domestic dual boiler machines cost between £1100 – £2000, depending on brand, build and additional features. DBs are traditionally, beautifully crafted machines designed for those that want ultimate performance and maximum control. They contain a digital system that monitors temperature (PID) and enable complete stability. They are highly convenient – there’s no waiting, no cooling flushes, and they allow you to make coffee to rival that of the best coffee shops in Edinburgh (and there are some very good ones!).

      See the Machina guide to choosing a grinder