Temperature and heating elements
Temperature:
The correct temperature of the brew group is of utmost importance for your espresso. For an espresso, this should generally be between 88 and 94 degrees during extraction. A darker roast looks better at a lower temperature, the lighter roasts require slightly higher temperatures. Correctly measuring the temperature in the group is very difficult with most espresso machines. Measuring the water that comes out with a thermometer does not give a correct measurement, because the flow is much too high to simulate making an espresso. This method of measuring always comes out too low because the group cools down too quickly. Without specialist measuring equipment you can see a lot from the crema or the effluent of the water:
- Crema: you can tell whether the machine has the right temperature by the color of the crema (provided espresso coffee, the correct grinding degree and dosage!) If the crema is too light in color, then the temperature is too low. If the crema becomes very dark or even disappears, the machine is overheating.
- Water outflow: the way water flows out of the brew group (without filter drag!)! is a good visual way to see if the temperature is heading in the right direction. The first water must come with some steam/vapor, the first water must be between 90 and 100 degrees. This steam should decrease quickly.
Adjust temperature: On machines with a heat exchanger, the pressure can be increased or decreased with the pressure switch or the PID (see E61 tips and tricks). Lime can cause the temperature to be too low. Machines with thermostats offer many different temperatures, which is fun to play with.
Heating element:
Your espresso machine contains a heating element to heat the water. Two main groups can be distinguished between the heating elements, thermoblocks and immersion elements. Machines such as QuickMill and La Piccola have a thermoblock, this form of heating rarely causes problems, so we will ignore it further. However, most machines have a so-called immersion element (further called a heating element on our site).
This element sits directly in the water in the boiler and must always be completely submerged. Because these elements are always under water, they suffer quite a bit from lime and other minerals in the water and can therefore sometimes break. This usually indicates an earth leakage circuit, when the copper sheath of the element no longer insulates sufficiently. The element can also burn out internally, causing the machine to simply no longer heat up. In the video below we explain how you can measure this:
Dismantling the heating element: Dismantling a heating element is best done with a long socket on an impact or air wrench. Never apply too much force with, for example, a long ratchet, because then the pipework will bend. Never place the boiler in a vice as it will dent. If in doubt or if you do not have the right tools, we recommend that you take the machine to a professional for repair.
Installing a new heating element: Installing the heating element is also best done using a long socket on an impact or air wrench. Always seal the thread of the element with Loxeal or PTFE tape to prevent leakage, the Teflon gasket does not always seal tightly enough.
Connecting a new heating element: If you install a new element in your boiler, it is important to take into account that it is an immersion element, so it must be completely submerged before voltage is applied! Regardless of the brand, make sure you fill the boiler completely before connecting the element wires. So always leave 1 or 2 poles of the element loose. Depending on the type of boiler, follow the following procedure:
- Espresso machines with heat exchanger (HX): First check whether the machine fills itself, these machines have a control box that regulates the water level in the boiler. Does your machine not fill itself automatically? Then the boiler probe or the control box is defective and that is also the cause of the defective element. See tips and tricks for the E61 machine for further steps.
- Espresso machines with a single boiler (Vibiemme Domobar
Standard, Rancilio, etc.): By turning on the coffee pump and
letting it pump until water comes out of the group, you can be sure
that the boiler is completely filled. In these machines, the
element often breaks down due to long periods of steaming. Always
refill the boiler after steaming in the same way as described
above.
- Dual boiler machines: If you replace the element of the coffee
boiler with a dual boiler, also follow the working method of the
continuous boiler. For the steam/service boiler, follow the method
of the heat exchanger. The element must first be completely
submerged in the water before it can heat up, otherwise it will
burn out immediately. If you are sure that the boiler is full,
remove the plug from the socket and only then connect the wires of
the element.
