What is the Thermoblock system?

The Thermoblock system is a water heating system used by some coffee machines (especially capsule coffee machines of most brands) to prepare the hot beverage in the shortest possible time. Using the Thermoblock heating system, coffee makers heat the water in approximately 20-30 seconds, while traditional heating elements take about two minutes to heat up.

The Thermoblock system consists of multiple internal pipes in a spiral through which the water circulates. When the coffee machine is switched on, the Thermoblock reaches a high temperature so that the water passing through it heats up in a very short time, which is logically the main advantage of this heating method.

Coffee machines using thermoblock are more efficient than traditional boilers, which have to heat all the water in an internal container. In the following image, we can see what a Thermoblock system looks like inside:

Thermoblock system inside
Thermoblock system inside

Advantages and disadvantages of the Thermoblock in coffee machines

In the Thermoblock system, the water is heated in a metal block or duct with several channels or tubes (see it correctly in the picture above). This compartment where the water is heated is quite small, and to heat all the water needed, the machine has to regulate the flow of liquid through the channels of the Thermoblock.

If the water flows too fast or too slow, it will not reach the right temperature, and the overall temperature of our coffee will not be stable and consistent, so the flow has to be precisely controlled. When a thermoblock is saturated by limescale, the water will flow more slowly, so the temperature will not be right.

thermoblock vs boiler
Thermoblock vs boiler

Related: How to descale a Dolce Gusto coffee machine.

In other words, the main advantage of the Thermoblock system in domestic coffee machines is that the coffee is ready more quickly, and the main disadvantage is that they are more affected by limescale and the water temperature is less stable than in coffee machines that use a boiler. For this reason, the Thermoblock is often installed in certain types of coffee machines, but not necessarily in all of them.

See this article: My coffee machine does not heat the water.

Which coffee machines use thermoblock and why?

As we have already mentioned, one of the advantages of the thermoblock is the speed with which they heat the water, even though they have poorer temperature control. This is why the thermoblock is included in all capsule coffee machines and most super-automatic coffee machines. However, group espresso machines usually have a classic boiler to brew coffee constantly at 93 degrees Celsius.

Thermoblock in espresso machines

If they have a steamer, most group espresso machines have a thermoblock unit dedicated for the steam. Because when we want to heat milk, it is not so important that the temperature is very constant, but it must be immediately high. However, in earlier espresso machines, the same boiler was used for the water and the steam, which made them more complicated and delicate.

Over time, espresso machines developed more efficient heating water and steam systems, including heat exchanger + boiler systems and double boiler systems (one for water and one for steam). Imagine two boilers in the same coffee machine; if a boiler is already much more bulky and expensive to manufacture than a thermoblock, the price and volume of the brewer will be higher with this configuration.