Water Softening

It is important to use only soft water to run on any types of coffee machines. Most limescale are calcium carbonate CaSO₄. CaCO₃ or MgCO will also make up a part of it, water softening is the most important step to follow in using any types of coffee makers.

Scale formation can cause serious problems to the machines, normally resulting in expensive repairs. It is often the main culprit to machine failure. Even if the machine is armed with the most heavy duty components, they can only work if they are not hindered by limescale blockage.

Restoration process like descaling is time-consuming and can cause irreversible damages to the components and metal in the process. Matter of fact, running the system with descaling liquid can’t reach all ends and clear all the limescale thoroughly.

As such, keeping the water condition soft is the most important step to extend the longevity of an espresso machine, it is much better to prevent limescale from building than performing too much descaling.


Here are some photos of limescale formation on espresso machines used in Singapore.

Water unable to flow

Stuck valves


Clogged pipe

Clogged pipe

Water leaks when valves can’t seal.

That is not all. Scales can cover the sensors, the heating elements, and cause the machine to malfunction. As scales are solids, the restoration process will be time-consuming as time is needed to dissolve the minerals and rinse them out of the machine. Many tests are also required after the restoration.



There are many solutions available on the market.

Do note that most water softeners reduce the amount of mineral in the water but do not eliminate totally. Most solutions will have its efficacy reduced over time and require regular maintenance or replacement. If the condition of the water is very hard, the amount of limescale might not be sufficiently reduced.

On the other hand,  not all water filtration systems are effective in reducing limescale. Some will do well in removing microbes, toxic and metal but does nothing to limescale. Also, certain water filtration systems may remove all the minerals totally, this will be a problem because the water may not be detected by machines using electrolysis to conduct a signal on its water condition. Meaning, the machine might have difficulty detecting there’s water in the water tank, or the water level in the boiler. In addition to that, water which is aggressively filtered to have zero mineral, similar to distilled water, will have an erosive effect on the yellow metal within the machine. Which can thin the metal layers, and leach into the water.

Please consult a water filtration specialist to advise for more appropriate solutions.

Water softening cartridge (Recommended)


Purchase Bezzera Water Softener here
Purchase OEM Water Softener here


This is the most common solution recommended by manufacturers for semi-professional espresso machines and is only effective for home or office environment with smaller usage.
Base on the water condition in Singapore, which has a hardness of about 7 French Degrees, the cartridge works for approximately 40 litres before they must be replaced.  If you are using mineral water or if you are using in some other countries, then the hardness might be much greater and you will have to replace the softener much earlier.


Before using, rinse water softener with clean water for 10 minutes. It’s important the water softener remains in the water and does not dry out. If resins dry out, it will no longer be effective in softening the water.


For Bezzera machines with a water tank of 4 litres, this includes but not limited to Magica, Mitica, Strega, BZ16, Galatea Domus. The water tank will require a little modification to accept a water cartridge.

Bezzera modification kit for softener

For machines that have a silicon suction hose like the Bezzera BZ07, BZ09, BZ10, BZ13, Expobar Pulser, Brewtus with Vibration pump, Leva EB61.

This little cartridge can be attached to the inlet hose directly. Please remove the dirt filter before attaching the softener.

Dirt filter

BILT Oscar 150 Water Softener

BILT Oscar 150 Water Softener


Purchase here

This is a bag of resins which you can place inside the water tank. It will cure the water but it will take some time to be effective.


Effectiveness guide and softening time.

Germen DegreesPPM mg/L CaCO3Min Softening time (Hours) Max Treated LitresDrinks (100cc)

Singapore’s PUB Water Quality Rating

Average : 66 mg/L

Range across Singapore : 26 – 203 mg/L

Expiry: 12 months from purchase date or upon finishing the maximum treated litres above.

The “Min Softening time” is the time it starts to reduce hardness, it’s recommended to have the softening prolonged for 2 to 4 times longer.
Users may want to soften water in advance, done by treating the water to be used in another water vessel before pouring into the espresso machine.


They are not suitable for all Expobar or any machines with water tanks that do not have openings wide enough to insert the Oscar water softeners


Other solutions:


1. Water pitchers with filters


We note that certain brands of water pitchers with built-in filters work in reducing the hardness of the water. The filter cartridge in the water pitcher has to be replaced regularly.
As we don’t carry such products, users will have to check with the vendor or manufacturer if their models do have the capability to soften the water.

Do note that some water filters with activated carbon produce carbon dust, which might get into the boiler and cause adverse effects.


2.Water filtration systems


Some users will prefer to use a filtration system.
If you are plumping in or you are expecting heavy usage, this will be the most recommended.
Again, users will have to check with the vendor or manufacturer if their models work in softening the water.

If the filter has activated carbon, it might produce carbon dust which can transfer to the boiler.

Also some systems might purify the water too much and has absolutely zero minerals in the water, almost like distilled water. This can be an issue as distilled water has an erosive effect on the yellow metal, and it might not ignite the water detection system going by conduction via electrolysis.


3.Distilled water

It is possible to use distilled water, but the water must be remineralised by adding some minerals back. Remineralisation keeps the water from being too erosive, which reduces metal leaching into the water.

Also, water level in the boiler is detected by the conduction via the water probes. Using distilled water will make such detection difficult or impossible, which can cause massive damages. If the process of remineralisation is properly done, it can form a layer of copper oxide on the yellow metal that protects it from further corrosion. Users who are particularly interested in exploring their coffee can use this method to control the taste by controlling the hardness.

To add the beneficial minerals back into the water.
We will suggest first adding 4.2 grams of sodium bicarbonate(baking soda) and dissolve it in 100 mL of distilled water to form a solution.
Add 2 mL of this bicarbonate solution to each litre of distilled water. This will give you 84 mg/litre.



Many manufacturers will recommend descaling which is running through the system with a food-grade acid to dissolve the limescale. This is almost equivalent to having chemotherapy for a cancer patient and it’s common to see users who had issues after performing the task.

Sometimes, it can cause worse clogging issues if the limescale is unable to fully dissolve and flake off from the walls. The solid residues will travel within the water network and might cause sealing issues among the gaskets which render the valves ineffective.

On the other hand, if descaling is done too intensely, it might erode the brass fittings and harmful metal starts to get released into the water. It doesn’t matter if your machine is using a stainless steel boiler as the fittings and grouphead is usually made of brass. Consciences brands like Bezzera began using food-grade metal which has a protective layer over it, but they can degenerate during the descaling process. We had also seen cases where users destroy their pump and heating element during the process. After all, we have to remind that vibration pumps have a duty cycle of 2:1, for every 2 minutes of work, it has to rest for a minute. The long and exhaustive process of descaling, can easily kill the pump if the user did not take heed and allow sufficient rest time.

Another problem is the descaling solution can only travel to where the water network can reach. This simply means that it cannot descale the top portion of the boiler, which is the place where we normally see limescale forming and where most of the key components are. Particularly the water probes, relieve valve, the safety valve that keeps the machine from exploding, and the pressurestat which controls the pressure and heat in the boiler. We had seen some users who had done a method recommended online which involved disconnecting the water probe and allow the pump to flood the boiler full. This method is quite dangerous when done incorrectly if the user forgot to remove open the tapes to release excess pressure. We had seen many users who had blown up their pressure gauge with this method.

Another method some users do is they dismantle every tube and boiler, and submerge into a pail of descaling liquid. This allows the user to visually inspect if limescale is all dissolved with no remaining residues in the boiler. The problem with this method is it’s very tedious, costly and at the same time, the process erodes both sides of the surface of the metal, inside and outside. This can decrease the structural integrity as well as thinning the walls of the metal, causing erosion and eventually holes to form, that condition is beyond repair.


Users should commit to preventive measures like water softening to keep the damage minimal. After 5-10 years, we will suggest checking for limescale especially if there’s observed abnormality. If the amount of limescale is very light, then good job, you shouldn’t need to do or worry much. A properly maintained machine will definitely last for decades with only a few minor repairs.

If limescale is spotted, then it’s inevitable that a light descaling as well as replacing some key components be necessary. You will never recover metal that gets eroded, which can cause the toxic in metal to start leaching.

For the same reason, that’s why it’s better to drink a coffee from your own machine than drink from a cafe that descale their machine every quarter!

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