Remember that there are established parameters to prepare an ideal espresso with a classic espresso machine. The requirements are:
- Use 7 grams of ground coffee.
- The coffee should have a relatively fine grind.
- The infusion should be made at 187 degrees Fahrenheit.
- The coffee in the cup should be at 160 degrees Fahrenheit.
- A ratio of coffee to water between 1:1.5 and 1:2.5
- The preparation should last 5 seconds of pre-infusion and 25 seconds of infusion.
- The final amount of coffee extracted should be 25 milliliters.
- The water pressure during brewing should be 9 bar.
The pressure exerted by the machine is essential to obtain good preparations. The Nespresso coffee makers have a maximum pressure of 20 bar ± 3 bar. However, these values refer to the pump’s design, not the working pressure.
Once started, it will work between 9 and 16 bars; this varies according to the type of coffee you use and the state in which the coffee maker is in. Then, coffee prepared with a pump that delivers less than 9 bars of pressure will be far from being a perfect coffee.
Why does my Nespresso lose pressure?
Note: If we plug our coffee maker into an incorrect power source, the water pressure will suddenly rise. But this happens rarely and does not represent a problem with the machine; for this reason, we will not deal with it in this article.
When there is a lack of pressure related to the water pump, the coffee maker itself will begin to show symptoms that something is wrong. The main symptom of the loss of pressure is directly related to the decrease in the volume of coffee we obtain in our preparations. Review our article on low-volume coffees.
It will always be necessary to ensure that the coffee maker is losing pressure and not assume it. For this reason, it will be necessary to reset the machine to the factory settings. With the factory settings, the volume obtained in the preparations corresponds to 40 ml for espressos and 110 ml for lungos.
To reset the settings, you only need to unplug the coffee maker, hold down the lungo button, plug in it again, and release it.
After resetting the settings, check that your coffee maker is serving less coffee with a measuring cup and test it by preparing both an espresso and a lungo. It would be very useful if you could videotape how the coffee comes out for later comparisons.
Low pressure due to lack of cleaning and maintenance
When there is an accumulation of limescale and other residues inside the coffee maker, the pressure of your machine will decrease in the preparations. In this specific case, it is recommended to descale the coffee maker immediately, once, or several times.
After performing this process, you can measure the coffee volume again to compare and corroborate that the problem has been solved.
Once decalcification is complete, you can move on to cleaning and maintenance of the front capsule piercing disc. With the help of an old toothbrush and a little clean water, scrub the disc thoroughly to remove all obstructions and dirt, and occasionally press the lungo button, without the capsule, to rinse.
If you followed our maintenance and cleaning recommendations in the letter, it is most likely that the problem with the pressure in your coffee maker has been solved. However, if the problem persists, we must rule out the cause that you will see in the following section.
Low pressure due to air penetration in the water circuit
The water circuit of Nespresso coffee machines is much simpler than that of other machines, but this does not mean that it can, at some point, present problems. Each connection between the valve and tube has an O-ring that, over time, tends to break and wreak havoc.
When one of these gaskets wears out or breaks permanently, it can cause air to enter the water circuit, which, in turn, will affect the pressure exerted by the machine to prepare the coffee.
It will be necessary to disassemble the coffee maker to identify if the air is entering the circuit; without the machine’s casing, prepare several coffees so you can observe if this problem is occurring.
Another consequence of damage to an O-ring is water leakage, so you should be alert to drips when pressure problems occur in your coffee maker.
Low pressure due to a defect in the water pump
Regularly descaling and cleaning your coffee maker can solve many problems, including the lack of pressure. But if, after a decalcification, the problem persists, we will have to concentrate on checking the water pump in depth. In this case, it will be necessary to disassemble the coffee maker to access the pump inside.
Once the Nespresso has been disassembled, observe if the pump shows visible external damage such as discoloration, rust, etc. If externally it appears to be fine, you may decide to replace it with a new one, or disassemble the pump and try to clean it very well and replace the O-rings if they are damaged: in either case, follow the recommendations below:
- If you buy a new pump, you should know its price ranges around $20 on Amazon. Before you buy it, make sure it has the same characteristics as the one you will replace.
- If you are a little more daring, try to disassemble the pump and check each component, in addition to a thorough cleaning. Be careful not to lose any part and when reassembling the pump, make sure that each part is very well adjusted, exactly in the same place where you removed it.