Water Softening

The following is applicable to almost any coffee machines, whether it’s a simple coffee maker you got from the electromart, or a commercial machine.

Most users are only concern about cleaning the brewing mechanism in their coffee machine, shown as Area 1 below. Issues found in this area are often minor. Most of the issues around the grouphead or wands are affiliated to wear and tear and they are rather simple to service. Sometimes, they may be minor leaks or slight irregular pressure issues, but that normally won’t put them beyond repair.

What many people fail to pay enough attention, is the boiler and water circuitry, featured as Area 2 above. Ask any experienced technician, and they will echo the same view that water softening is the most important maintenance step for any types of coffee machine. In such complex boiler heated espresso machines, damages from limescale are considered abuse of usage and are normally not covered in the warranty, especially if the user intentionally use mineral water or filters that remineralise.

Why do we need to soften?
In the water, there are minerals, and these form limescale. Most limescale are made of calcium sulphate CaSO₄, calcium carbonate CaCO₃ or Magnesium Carbonate MgCO₃. What limescale does is they will consolidate and form solids particles. They tend to get larger until they choke the water passage or obstruct seals from closing. Whether is it entirely or partially, it can cause enough damages for the machine to fail. When the machine is choked, you may encounter pressure issues, or heat issues which can link to other components to malfunction altogether.

Once an area is spotted to have limescale, it’s a sign that the entire water network and many connected components are plagued with it. This can cause all sorts of issues resulting in very expensive repairs. Unless you get an overhaul, there’s no guarantee that a technician can clear all the limescale to keep problems from coming.

Even if the machine is fitted with the most heavy-duty components, the components can only be as effective as they are not obstructed. The best thing a user can do is to avoid the situation by keeping the water soft. Limescale free machines are capable of running for decades with minimal repairs. It is much easier and economical to prevent limescale from building than finding ways to get rid of them later.  


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

Issue: Water unable to flow.

Issue: Seals on valves unable to fully close, unstable water pressure.

Clogged pipe

Issue: Clogged pipe, water unable to flow

pressurestat choked

Issues: Pressure/heat controller choked, machine unable to detect when to start or stop heating.

Issue: Valves can’t seal causing leaks.

That is not all. Limescale can cover the sensors, the heating elements or obstruct the different valves. Imagine this, the pressure sensor is coated with limescale and can’t detect, the heating element keeps heating, and burn itself out. Problem with one component can result in problems to others. This means very expensive repairs as it is almost an overhaul to replace everything.

How long does it take for limescale to form?
This can’t be answered easily. This depends on how hard is the water and how much hard water goes through the machine

We had seen users who used bottled mineral water or water filtration systems that remineralise. Coming back with multiple problems within months and the inside looks like it’s been used for years.

Like cancer, some users are luckier, we had encountered users with a boiler full of limescale but managed to make it work for a decade. Such examples are few. We do know that their luck will eventually run out. We had seen far more unlucky ones with machines defeated with a tiny speck of limescale. Sometimes, just a bit of limescale at a critical valve, is enough to cause the machine to malfunction.

We had never met a user who regret using a water softener but met plenty who regret not using them. Spending on softeners or treating the water can definitely ward off large service bills.



Many retailers 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 stage 4 cancer patient. It does help as a preventive measure to a certain point but there are caveats to note. Having said that, a regularly descaled machine normally have a smaller bill for repair as some parts of the water circuitry and most of the boiler are cleared.

There are a number of potential issues which are unfortunately common after descaling. We had noticed that quite a number of machines that had done descaling were eventually returned for repairs. Especially if they use the wrong type of descaler.

Clogging issues
Not all types of limescale can be dissolved with acid. If the limescale is unable to fully dissolve and flake off from the walls. The solid residues will travel through the water network and might end up in a valve. This might cause sealing problems which render the valves ineffective, causing unusual water pressure or heating issues. Concentrated limescale, especially sulphates are difficult to dissolve with both light or strong acid that is commonly used in descalers.

On the other hand, if descaling is done too intensely, it might erode the brass fittings and harmful metal gets released into the water. It doesn’t matter if your machine is using a stainless steel boiler as the fittings and grouphead are usually still made of brass for its heat conductivity. It is the brass that has to be worried off as brass might start leaching much more lead after corrosion. Consciences brands like Bezzera began using food-grade brass that has almost no lead, on top of it, they plate a protective layer over it. Most importantly, they don’t use brass boilers which have constant contact with the water inside. However, the additional protections may slightly degenerate from the acid bath during descaling.

Damages to key components
It is not uncommon to see users destroying their pump and heating element while descaling. This is particularly common with vibration pumps which have a duty cycle and can burn itself out from the taxing descaling process or damaged by the descaler itself.

Vibration pumps used on our machines have a duty cycle of 2:1. For every 2 minutes of work, it has to rest for a minute. For domestic machines found in electromarts, their duty cycle is usually rated 1:1 or 1.5:1. The long and exhaustive process of descaling, can easily kill the pump if the user did not take heed and allow sufficient rest time.

Some users destroyed their machines when they followed some dangerous methods found online. Which recommend disconnecting the water probes and allow the pump to flood the boiler full. This method can be quite dangerous if not correctly done. If the user forgot to open the wands to vent excess pressure, water will enter into the gauges and destroy them, it might also exert too much pressure on the other components. We had also seen users who had used descalers that are too strong or concentrated and destroyed the heating element.

If you are not aware, damages due to limescale and the descaling process voids the warranty for most high-end machine. The descaling process can be dangerous if incorrectly done. 

Difficult to descale 100%
If you thought that you can really clear off all the limescale by doing descaling, you might be disappointed.

The descaler can’t reach every corner in the machine. Most importantly, it cannot reach the top of the boiler where we normally see limescale form. Some users assumed that limescale will only be formed at places where the water can reach, this is not true. Matter of fact, it’s very common to see limescale forming on many of the components located on top of the boiler.

espresso machine on all the time
Descaler can’t reach the top of the boiler where limescale often form.

The components located on top of the boiler includes the water probes that sense water or temperature, relieve valve that bleeds excess air, the safety valve that keeps the machine from exploding, and the pressurestat which controls the pressure and heat in the boiler. It will also not descale some valves that are only open under certain conditions. So it might be a wasted effort, not addressing the issue.

Some technicians dismantle every fitting, tubes and the boiler, and submerge everything into a pail of descaling liquid. This is very tedious, which translate to a higher cost for workmanship. At the same time, the process corrode both sides of the metal’s wall, inside and outside, thinning down the metal. This increase the risk of holes to form, such condition is considered beyond repair as it would be too costly to replace. Also, you can’t throw some electronic components like the pressurestat entirely into the descaler to clean the inside, so it still won’t be a 100%. It is quite unlikely that the technician can really visually check every part as many areas are out of view.

Descalers don’t work at many times
Most descalers sold in the market are weak acid that has to be heated up to be effective. Citric and vinegar are examples of weak acid. In any case, they usually work very slowly. They are unable to penetrate into thick limescales fast enough and dissolve all of them. Also, you should never feed your machine with hot water, it will easily cause cold water tube connectors to expand. This causes the tubes to detach from the fitting and cause major leaks. If you want to use a descaler that works cold, you will need something like Pulycaff Liquid Descaler.

Weak acid may get rid of contact calcium carbonate CaCO₃ or Magnesium Carbonate MgCO₃. However, they work too slowly and some compartments are only opened for brief moments during the descaling process. Using a stronger descaler like the Pulycaff Liquid Descaler can be a lot more effective as they react many times faster.

Unfortunately, most descalers won’t do much to limescale made up of calcium sulphate CaSO₄. Calcium sulphate is normally formed when the user uses the steam wand a lot. That vaporizes the water but leaves behind a higher concentration of minerals in the boiler forming the sulphates.

To get rid of calcium sulphate, user may want to use distilled water for months to have the sulphate dissolved. Distilled water at room temperature has a little erosive effect that can dissolve the sulphate gradually.


Flush your boiler regularly

One of the things that we recommend users to do every 2-6 month is to empty the boiler and renew the tank with fresh filtered water. If you use the steam wand a lot, then you might want to do it more often.

This will renew the water in the boiler so mineral won’t be as concentrated and calcium sulphate won’t form easily.

To flush your steam boiler, simply heat up your machine till it builds enough pressure. Switch off the machine then purge all the water using the water wand. Then refill the boiler with a fresh tank of clean softened water.

Here’s a good video from whole latte love on how to drain a heat exchanger machine.

If your machine is using a vibration pump, one thing you got to take note of is you should do it slowly while refilling the boiler, so the pump won’t overheat and destroy itself, as we mentioned earlier that vibe pumps have duty cycle. We will suggest letting the pump work for one minute and rest for another minute before going for another minute of work.

If you had not flushed your boiler for a long time, don’t be alarm that the water is a little brownish or seeing some sediments. The machine don’t grow any sediments from nowhere, the sediments are from the water.

Use water softeners

Most water softeners can only reduce the amount of mineral in the water but can’t eliminate totally.  Efficacy of the softener will reduce over time and will require regular maintenance or replacement. If the condition of the water is very hard, you might need a more effective softener or have it replaced more often.

Water softening cartridge (Recommended)

Purchase Bezzera Water Softener here

This is the easiest and most common solution recommended by manufacturers for semi-professional espresso machines.  This will only work if the machine draws water from an internal water tank. If you are thinking of connecting your machine to the tap, this cartridge won’t work.

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 other countries, then the hardness might be much greater and you will have to replace the softener much earlier.

Resins in water softeners can’t really be more effective, so be careful of products that oversell that they can do more litres per cartridge.

Before using, rinse the water softener with clean water for 10 minutes or have it submerged for around 20 minutes. You must not allow the softener to dry up. If the resins inside are dried up, it will no longer be effective.

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

Bezzera modification kit for softener

For machines that draw water from a silicone inlet hose like the Bezzera BZ07, BZ09, BZ10, BZ13, Crema, Expobar Pulser, Brewtus with Vibration pump, Leva EB61, etc. This little cartridge can be attached to the inlet hose directly, you don’t need to do any modification but you should remove the dirt filter before attaching the softener.

For other brands, if your machine is drawing water from a silicone hose like what’s pictured above, then it’s most likely compatible.

 Water pitchers with filters

We are aware that certain brands of water pitchers with built-in filters can reduce the hardness of the water.

The type of filters used varies between brands and models, so it’s hard to judge. 

The filter cartridge in the water pitcher has to be replaced regularly.  In our experience, these filters don’t work for that long, the user also has to do an extra step of transferring water into the pitcher before it is usable, so we don’t think it’s the best solution.

As we don’t carry such products, users will have to check with the vendor or manufacturer to check its efficacy in softening the water.

Be aware that if the water filters has activated carbon in it. The filter might release carbon dust, which might get into the boiler and cause adverse effects.

Water filtration systems

If you are planning to plumb your machine directly to the tap or you prefer a whole house water filtration system, then you will need to look at this.

Water filtration systems are larger canisters of filters placed along the water network to filter a larger amount of water. 

Before you purchase any filters, do note that most filtration systems don’t work. Most water filtration systems sold in Singapore are designed to remove toxin, microbes, metal and debris, but does nothing much for softening. Or they won’t remain effective for softening for long.

Also, some water filtration systems are very aggressive and may totally strip off all the minerals in the water. The water produced in this way, is very similar to distilled water. Normally such ultra-clean waters are used for industrial production purposes, but somehow they are been sold to home or F&B industries nowadays.  The problem with distilled water is they are erosive, gradually stripping metal surfaces. This will thin the metal and the eroded toxic metal goes into the water and into your drink. The water probes and sensors in the machine might not be able to detect such ultra-pure water in the boiler and the machine can malfunction causing serious damages.

To counter the use of overly pure water, some Bezzera espresso machines detect water in the water tank by electrolysis.  It works by sending a signal in the water and detecting at the other end of the water tank. For distilled water, the signal cannot be transferred and the machine won’t operate, as it assumes that there’s no water in the water tank.

Last, there are water filtration systems that remineralise. The reason why they remineralise is to add some beneficial minerals back to the filtered water. To make the water less erosive and adding minerals beneficial to the drinker, but such treated water is often deadly to the machine. We had seen users who returned machines that look like having a decade amount of limescale accumulated using such water for merely months. Limescale damages are often not covered in manufacturer’s warranty as they are considered abuse or wear and tear.

If you intend to purchase a commercial filtration system, it is best to speak to the manufacturer and ask them specifically if their product can soften successfully and how long they can remain effective. Filters that have softening capabilities, should state very clearly of its efficacy, of how much water it can process according to the different water hardness levels. If the vendor or supplier is unable to produce the information, it is most likely that the filter is not intended for water softening.

Again, most filters in Singapore are not meant for softening. Also, if the filter has activated carbon, it might release carbon dust which might end up in the boiler if they are not flushed away first.

Users have to be clear of how many litres of water can the softener be effective for. Most softeners are only good for a few hundred to a few thousand litres before replacement or regeneration. A few hundred or thousand litres for whole-house filtration isn’t considered a lot. If the softener is placed before a tap and is also used for other purposes like a dishwasher, for the tap, etc. It might deplete the life of the softener very quickly. We will suggest that the softener be dedicated for the espresso machine only, and a schedule should be made to correctly determine when the cartridge should be replaced or regenerated.

Some water softeners can be regenerated with brine, but it is very important to thoroughly rinse off the salt as saltwater is highly corrosive to metal.

Distilled water

As mentioned earlier, distilled water by itself is erosive and should not be used most of the time. Being erosive means it will strip metal and bring toxic to the water, or the metal starts to be toxic as the protective layer is gone. Also as mentioned earlier, your machine’s water probe might go haywire and could not detect the water in the boiler properly, causing the machine to malfunction and creates damages.

However, room temperature distilled water can be used to gradually dissolve limescale composed of calcium sulfate but not effective to limescale made of calcium bicarbonate and magnesium bicarbonate. This can be somehow beneficial for some machines with a boiler already full of hard water. 

Like what was said before, some machines detect and reject the use of distilled water as a precautionary feature. By Bezzera’s opinion, they think it should be totally avoided. Some of Bezzera’s machines will not be able to detect that the water tank is full when water of such purity is being used. You can bypass the water tank’s sensor though, but we will not be responsible for any damages that might happen.

Remineralised distilled water

There’s a chemist way of treating distilled water to be usable. This might be the best method and beneficial in many ways. It sounds complicated but it’s not really difficult. Doing this saves you a lot of woes in future. Using this method will mean that limescale will almost never form in the machine. This adds a lot of longevity to the life of your machine. Even when there’s an issue, repairs are likely to be less costly as problems are isolated within the affected components.

In addition to that, the copper wall will form a dark layer of copper oxide which is a good additional protection. Lastly, the user can slightly influence the taste of their espresso as they can manipulate how hard is their water.

To do that, the distilled water must be remineralised by adding some minerals back to negate its erosiveness. 

To add the beneficial minerals back into the water. We will suggest using the following formula and should be done with either sodium bicarbonate or potassium bicarbonate.

Using Sodium Bicarbonate(NaHCO₃ aka baking soda)
1. Add 4.2 grams of sodium bicarbonate(baking soda) and dissolve it in 100 mL of distilled water to form a solution.
2. Add 2 mL of this bicarbonate solution to each litre of distilled water. This will give you 84 mg/litre.

Using Potassium Bicarbonate (KHCO₃)
1. Add 10 grams of Potassium Bicarbonate (K₂CO) and dissolve it in 100 mL of distilled water to form a solution.
2. Add 1 mL of this bicarbonate solution to each litre of distilled water. This will give you 100 mg/litre.


Users should commit to preventive measures like water softening to keep limescale damages minimal. As we had mentioned above, it’s more economical and easier to soften the water than to think of how to get rid of the limescale later.

After 5-10 years, if you think the machine has some issues, you can send it back to us for a check and replace a few key components. If the amount of limescale is very mild, then you shouldn’t need to do or worry much. A properly maintained machine will definitely last for decades with only a few parts replacement.

If some limescale is spotted, then it’s better to perform a light descaling in additional to replacing some components. Some valves are better replaced than cleaned, as you also replace the valves with new seals. Doing descaling regularly is more or less still alright but 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 much safer and better to drink a coffee from your own machine than to drink from a cafe that descales their machine every quarter!

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