Single Boiler | Single boiler espresso machines have one boiler for steam production and espresso brewing. These machines have 2 thermostats to separately control the steam and brew temperature.
While you arenít able to steam milk and brew coffee simultaneously, itís quite simple to get the rhythm of heating to steam mode, frothing your milk, cooling the machine down, preparing your espresso and then pouring your latte or cappuccino.
Heat Exchanger | Heat exchange machines have a single boiler that is always set to steam temperature. A metal tube runs through the boiler, which flash heats the water at around 200 degrees to the grouphead. This clever design delivers fresh water from the pump to the grouphead, and mimics the capabilities of a double boiler machine.
With a heat exchanger machine, dry steam and hot water are available at all times, without the need to flip any switches or switch any modes. Also, you are able to steam your milk and brew your coffee at the same time, leading to the freshest, professional-style latte.
Double Boiler | Double boiler espresso machines have one boiler each for steam and espresso. You can steam and pull shots simultaneously. Additionally, the steam boiler has a dedicated power switch, which gives the user the option to provide power only to the group head boiler if milk steaming wonít be necessary.