A thermoblock and a thermocoil are both heating elements for an espresso machine. A thermocoil is a modern and more efficient way of heating the machine, but it's also more expensive to make as it's a solid piece of steel. A thermoblock is composed of two parts of steel welded together. It's more prone to breaking, but can be made at a lower cost.
Having the ability to make an espresso drink whenever the mood strikes, is one of the great perks of having your own espresso machine. One thing you may notice is that some machines have a thermoblock and others have a thermocoil. You’re probably wondering what they do and how they differ.
We will explain the pros and cons of each so that you can make a more informed decision when shopping for an espresso machine.
Less expensive, smaller espresso machines intended to for use in a home or small office setting, don’t have boilers like the larger, industrial machines. A thermoblock is a heating mechanism that takes water from the reservoir in the espresso machine and heats it up as needed. Boilers in larger espresso machines heat and hold hot water, so it’s always ready.
Learn more about boiler espresso machines: Thermoblock vs. Boiler.
Thermoblock heat is beneficial because it doesn’t take long for the water to heat up. When the water runs through the thermoblock, which looks a bit like a maze, there are heating elements inside of the block that flash-heat the water as it flows through the block. By the time it exits, it’s hot enough to steam milk or to pull an espresso shot.
Another plus is that you can also save energy costs by not leaving the machine on all day long. If you had a machine with a boiler, it would take over 10 minutes for the machine to be ready to use. There may be some days you use your machine and other days not.
One of the drawbacks of a thermoblock, which is typically installed in older models of espresso machines, is that the block comes in two pieces and is prone to leaking. A crack in the block can affect the water temperature. Thermoblocks, while quick at heating water, may not always heat water consistently.
Thermoblocks are also prone to scaling, which can clog up your machine and make water flow inefficiently.
Thermocoils serve the same basic function as a thermoblock, to flash-heat the water. As you look at newer models of espresso machines, you may notice that thermocoils are starting to replace thermoblocks.
Thermocoils are a one-piece cylinder that flash heats water in multiple holes. One benefit to the thermocoil is that it’s less likely to leak. Another is more consistent water temperature. The water flows, circularly, until it’s heated and by the time it exits the thermocoil it’s hot enough to use. Due to the design of the thermocoil, the water heats more evenly.
Much like the thermoblock, thermocoils are prone to scaling. There are ways to descale the machine, but it can be time-consuming and a hassle. Another complaint of thermocoils (as well as thermoblocks) is that the heating mechanism cools down too quickly.
When this happens, you may have consistent heat for espresso shots, but not for steaming and frothing milk. As a result, it can also be difficult to make multiple drinks at a time. Even if it only takes a short time to heat the water again, you may not be patient enough to wait.