Sometimes it can be hard to separate marketing fluff from valuable features when you are shopping for an espresso machine. One of the elements of a machine that has many variations is boiler configuration. From single boilers, to heat exchangers, to thermoblocks, and more, there are many different types of boilers out there. Dual boilers are a classic standby in the espresso world, so we wanted to talk about them a bit and help you understand if they're worth the extra cost that comes with them.
What is a Dual Boiler Espresso Machine?
The boiler is the part of the espresso machine that heats water to be pumped to the group head and through the portafilter. Given that heat is one of the most important aspects of making espresso, the way it's heated matters.
Thermoblocks and thermojets heat water quickly, but often lack a bit of oomph in the steam department. Single boiler machines like the Rancilio Silvia are basic and provide good all around performance, but because brewing and steam is done from the same water source you will usually have to wait for temps to adjust for what you need. Heat exchangers, like the Rocket Appartamento, give you the capability to brew and steam at the same time, but lack temperature precision through the whole process.
Then there's dual boilers. These machines, such as the Diletta Alto, feature two boilers, one dedicated to steaming, and one to brewing. This means that not only can you steam and brew simultaneously, but you can independently control the temperatures of the boilers. This allows you to hit very precise brew temperatures while steaming.
So why is this useful?
Do I Need a Dual Boiler Espresso Machine?
The main benefit to this temperature precision is that it gives you the ability to brew very tricky roasts as espresso that may normally be hard to dial in. When you're dealing with temperatures that fluctuate due to heat up and cool down time for steam power it can be difficult to really nail those to the degree temperatures needed to make those tricky roasts work.
Then there's the simultaneous brewing and steaming. This capability mirrors commercial machines, and may be a workflow item that really matters to you. It takes practice to be able to flip on the water pump and the steam wand at the same time and get great results, but when you do it is incredibly satisfying.
Finally there's capacity. If you're brewing drinks for multiple people, or just making a couple of drinks in quick succession for yourself, the capacity of a dual boiler machine is a game changer. Normally after brewing and steaming on a single boiler machine you'll likely have depleted the water enough that the boiler will need time to recover. With a dual boiler machine you'll be able to cut down or eliminate that recovery.
So whether or not you need a dual boiler espresso machine is, as usual, down to your preferences and what kind of brewing habits you'd like to develop. These are powerful options that put a lot of control at your fingertips, but may be more than some users need.
You can learn more about dual boiler espresso machine in the video below. We'd love to hear from you about your favorite boiler configurations in the comments on this post as well!