Heat exchange espresso coffee machines use a metal heat exchanger to heat brewing water by using heat transferred from the main boiler. Heat exhanger machines have a single water filled boiler used to provide steam from the top of the boiler and hot water from the bottom of the boiler. This boiler is heated to over 100 degrees celcius to deliver hot dry steam. A metal tube (heat exchagner) runs through the boiler used for heating brewing water. Fresh water for coffee brewing is pump into the heat exchagner where it is heated to 88-92 degress celcius before passing into the brewing group. by rs are the most common style of commercial espresso machine used.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.
Heat exchanger espresso coffee machines allow the user to draw off dry steam and hot water at any time. Brewing of coffee can be conducted independent of steam or water function. You are able to steam milk and brew coffee at the same time which can make the coffee making process quicker.