We have received many questions about single vs. double boiler espresso machines. This entry will hopefully clear up any questions when you are doing your research and ready to purchase an espresso machine.
Why do you need 2 different temperatures? Short answer: Espresso is best when the coffee is extracted between 198-204 degrees Fahrenheit - which is below boiling point. However, for other drinks such as lattes or milk-based espressos, the steam for the milk requires a large amount of steam at a temperature well above boiling. Now that we understand why you need more than 1 temperature let's explore the single vs. double boiler to help you in purchasing the perfect machine.
What is the single boiler machine? The single boiler with a dual thermostat is one option. This allows you to control the temperature in the settings panel while you are at each step in the drink making process. This process will take more time though as the machine has to acclimate to each temperature setting.
The double boiler machine allows one temperature to be set up for brew and one for steam. This allows the proper temperature to be set at each phase without the lag time of the single boiler machine.
Another option is a Heat Exchanger machine. A heat exchanger espresso machine uses a single boiler that keeps the water at steam temperature but uses a cool water that is flash heated instantly to brew temperature when ready to pull the espresso shot.
Given the information above- which do you need? We recommend asking yourself - how you will use the espresso machine? How many cups per day will you serve? How often will you use the machine? Will you use the machine mainly for espressos or other drinks such as lattes? Once you answer these, you will be ready to move forward.