A thermoblock is one of the two most common heating methods in espresso machines. In this article, we will discuss everything there is to know.
In addition to the traditional boiler system, the thermoblock is frequently used, especially in the more compact and accessible espresso machines. It can be used as a stand-alone heating element that heats the cold water and transports it directly to the brewing group. There are also machines that use both a boiler and thermoblock. In this case, the thermoblock acts as an additional heating element directly above the brewing group to regulate the temperature as constant as possible.
The thermoblock system
The thermoblock works according to a simple but ingenious system. Simply put, it consists of a long, rolled-up tube through which water is pumped. In addition to the tube, it contains heating elements that heat the water that flows through the pipe. When the pipe has the right diameter and length, and the water is pumped through the thermoblock at the right rate, the water will eventually have the right temperature for espresso. The coiled pipe and the heating elements are cast in an aluminum block, hence the name ‘thermoblock’.
Advantage and disadvantages
Among other things, it has the advantage that the heating time is significantly shorter compared to a conventional boiler machine. Thermoblock espresso machines heat according to need, which means that the water does not have to be heated beforehand like with a boiler. Also, the water in the pipes is discharged directly. This gives lime no chance to adhere to the wall of the pipe.
Disadvantages include the fact these machines are not as good at producing steam. You will find that the steam from these machines often contains more moisture and has little pressure. This happens because the machine sends water through the thermoblock with short pulses which will result in steam. Because the steam is produced on demand, it can never contain as much pressure as in a boiler system, where the pressure already exists and is released from the boiler. Besides that, it’s also less stable in terms of temperature than a boiler system.
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