Regular scale can damage even the most expensive coffee machine in just a few months of active use. Hard water flowing through heating elements leaves a hard limescale deposit on the walls of the tubes and boiler, which reduces thermal conductivity and increases the load on the pump. Many equipment owners prefer to use folk remedies, such as citric acid, considering them a safer and cheaper alternative to expensive branded decalcifiers.
However, the process decalcification using food acids requires strict adherence to proportions and technology so as not to damage the rubber seals and plastic parts of the hydraulic system. An incorrectly prepared solution may be too aggressive or, conversely, ineffective against old deposits. In this article, we will look in detail at how to prepare the product correctly, what nuances there are for different types of coffee machines, and how to avoid common mistakes during maintenance.
Why scale forms and why citric acid is dangerous
The main cause of scale is calcium and magnesium salts contained in tap water. When heated, these salts precipitate, forming a dense crust on heating elements (tubular electric heaters) and in narrow channels of the brewing unit. Over time, the lumen of the tubes narrows, the water pressure drops, and the brewing temperature becomes unstable, which directly affects the taste espresso and cappuccino.
Citric acid (C6H8O7) is a weak organic acid that reacts effectively with calcium carbonates, converting them into soluble salts. Unlike acetic acid, it does not have a pungent odor and is less aggressive towards metals, but requires the correct temperature to activate. At temperatures above 60 degrees Celsius, the scale decomposition reaction occurs much faster and deeper.
Despite its relative safety, a concentrated acid solution can have a negative effect on some species. rubber productsused in coffee machines. Prolonged contact with a highly concentrated solution can cause O-rings to dry out or crack, leading to leaks. That is why it is important to maintain a balance between the effectiveness of the cleaning product and careful handling of materials.
⚠️ Attention: Never use pure citric acid powder without first dissolving it in water. Crystals entering the heating element can cause local overheating and damage to the coating of the heating element.
It is important to understand that decalcification - this is not a panacea for all ills, but a preventive measure. If the coffee machine has been running on very hard water for years without maintenance, a single rinse with a weak solution may not work, and using too strong a concentration will damage the device. In such cases, professional disassembly and mechanical cleaning of the units is required.
Solution proportions and preparation for cleaning
The key to successful and safe cleaning is the correct acid to water ratio. The standard and safest solution is considered to be a solution with a concentration of 5-7%. To prepare it, you usually use 30 grams of powder (about 1.5 level tablespoons) per 1.5 liters of water. This mixture effectively removes fresh deposits without damaging internal contours coffee machines.
For regions with very hard water or in the presence of visible signs of severe pollution, an increase in concentration of up to 10% is allowed, but no more. Exceeding this threshold creates a risk of damage to plastic parts and metal alloys, especially in budget models that use less acid-resistant materials. Always use warm water (about 40-50 degrees) to dissolve the crystals faster and more completely.
Use only distilled or filtered water to prepare the solution - this will prevent the formation of new deposits immediately during the cleaning process.
Before starting the procedure, be sure to empty the water tank of any remaining old liquid and rinse it. Pour the prepared warm solution into the tank. If your coffee machine is equipped with a decalcification indicator, it may light up immediately after switching on, confirming the urgency of the procedure. Some models DeLonghi or Krups You will need to first put the device into a special service mode.
Do not forget that the volume of solution must be sufficient for a full flushing cycle, which usually takes from 15 to 30 minutes depending on the model. Insufficient fluid may cause acid to remain in the system, which is unacceptable. It is better to prepare the solution with a small reserve so as not to interrupt the process halfway.
Step-by-step instructions: how to clean a coffee machine
The cleaning process varies depending on the type of coffee machine: drip, carob (pump) or automatic. However, the general principle remains the same: the solution must pass through the entire hydraulic system, heat up and contact the heating element. Automatic models often require activation of a special mode through the menu Service or Descaling.
In carob coffee makers without an automatic cleaning cycle, the process is carried out manually by alternating the supply of water and steam. Care must be taken to ensure that the hot solution does not fall directly on the cold parts of the housing, causing thermal shock. After half the solution has passed through the system, it is recommended to pause for 10-15 minutes so that the acid has a more active effect on calcareous deposits.
☑️ Checklist for preparing for decalcification
After all the acid solution has passed through the system, you must thoroughly rinse the coffee machine with clean water. To do this, the tank is filled with fresh water, and the run cycle is repeated 2-3 times. This is a critical step, as residual acid can give the coffee an unpleasant sour taste and a metallic aftertaste. The output water should be absolutely clear and neutral in taste.
If your coffee machine model has a removable brewing unit, it is also recommended to remove it and rinse it separately under running warm water, removing any remaining coffee oils. However, you should not immerse the electrical parts or the brewing unit itself in the acid solution - only the internal hydraulic system can be decalcified.
Features of cleaning different types of coffee machines
Different designs of coffee machines dictate their own maintenance rules. Owners drip coffee makers are the luckiest of all: their design is as simple as possible, and the risk of damaging something with acid is minimal. It is enough to pour the solution into the upper reservoir and turn on the cooking mode, allowing the liquid to pass through the filter and collect in the jug. Then the procedure is repeated with clean water.
C carob With (pump-action) machines the situation is more complicated. It is important here not to overheat the pump while running idle. Many models such as Bork or Vitek, do not have an automatic cycle, so the user has to manually switch between the “water” and “steam” modes, controlling the temperature. The boiler capillary tube in such machines is often the first to become clogged, and the acid helps to break through these narrow passages.
Automatic coffee machines, e.g. Saeco or Philips, have built-in decalcification algorithms. When starting the program, the machine itself doses the solution, makes the necessary pauses and rinses. There is no need to interfere with this process, but you should strictly follow the instructions on the display. Interrupting the cycle may cause the machine to “remember” the error and require service intervention.
| Coffee machine type | Recommended concentration | Solution temperature | Process nuances |
|---|---|---|---|
| Drip | 30 g per 1.5 l | Room / Warm | Simple pass through filter |
| Horn (pump) | 20-25 g per 1 l | 40-50 °C | Manual mode switching, pump control |
| Automatic | Follow instructions | The car heats itself | Strictly according to the menu, do not interrupt the cycle |
| Capsule | 10-15 g per 1 l | Room | Use an empty capsule or special. mode |
Dosage table and frequency of procedures
The frequency of the decalcification procedure directly depends on the hardness of the water in your region and the intensity of use of the coffee machine. If you use tap water, cleaning should be done every 2-3 months with heavy use (5-10 cups per day). When using filtered or bottled water, the interval can be extended to 4-6 months.
There are indirect signs that indicate that scale has already begun to interfere with the operation of the device. First of all, this is a change in the sound of the pump - it becomes more strained and louder. The preparation time for the espresso shot may also increase, and the stream of steam from the cappuccino maker may become weak and intermittent.
Below is a table to help determine the required maintenance frequency depending on operating conditions. Remember that prevention is always cheaper than repair, so it’s better to clean it a little earlier than wait for problems to appear.
It is important to keep a record of the last cleaning dates, especially in offices or coffee shops where equipment is used by different people. A sticker on the water tank with the next service date is a simple and effective way to monitor the condition of your equipment.
Precautions and common mistakes
Despite its natural origin, citric acid is a chemical reagent and requires careful handling. When working with a concentrated solution or powder, avoid contact of the substance with the eyes and exposed skin. In case of contact, rinse the affected area with plenty of running water.
⚠️ Attention: It is strictly forbidden to mix citric acid with chlorine-containing detergents or other acids. This may result in the release of toxic gases that are hazardous to health.
One of the most common mistakes is using too hot water to prepare the solution. Boiling water can cause a violent reaction with the formation of foam, which will overflow the edge of the tank, and will also accelerate the corrosion of metal elements before cleaning begins. The optimal temperature is warm, but not hot water.
Another mistake is ignoring the final rinsing step. The acid residue not only spoils the taste of the coffee, but also continues to attack the materials in the system while you drink the drink. If after three cycles of rinsing with water the taste is still sour, repeat the procedure 1-2 more times.
What should I do if a strange taste appears after cleaning?
If, after thorough rinsing, the acidic taste remains, it is possible that some of the solution is retained in hard-to-reach areas of the brewing unit. Remove the unit, wash it under warm water without detergents and let it dry. Also check the cleanliness of the cappuccino maker - often acid residues get stuck in the milk tube.
Alternative remedies and comparison with chemistry
There are many specialized descaling products on the market, such as Urgento, TopHouse or original solutions from coffee machine manufacturers. These products are formulated to suit the alloys and plastics used in specific applications and often contain corrosion inhibitors and seal lubricants.
The main advantage of specialized chemistry is the predictability of the result and the availability of all necessary safety certificates. Citric acid, being a food product, does not undergo the same compatibility tests with engineered polymers. However, the cost of branded products is much higher, which makes the “folk” method popular among budget-conscious users.
It is worth noting that acetic acid, which is also often recommended on the Internet, is more aggressive and has a persistent odor that is very difficult to flush out of the system. Citric acid wins in this regard, since it is volatile and washes out more easily, without leaving a characteristic aroma in a cup of coffee.
Specialized products are preferable for expensive automatic coffee machines with a warranty, while citric acid is an excellent choice for simple carob and drip models.
Frequently asked questions (FAQ)
Can citric acid be used in coffee machines with a built-in filter?
Yes, you can, but before filling the solution, the filter cartridge (for example, Intenza or AquaFilter) must be removed. The acid can destroy the structure of the filter media and wash accumulated contaminants back into the system, as well as damage the ion exchange resin.
How often should you change the water in the tank if the car is sitting idle?
If the coffee machine has not been used for more than 2-3 days, it is better to drain the water from the reservoir. Stagnant water is an ideal environment for bacteria to grow and form biofilm, which then mixes with scale and complicates the cleaning process. Before next use, flush the system with a hot water cycle without coffee.
Is citric acid harmful to aluminum boilers?
Aluminum and its alloys are sensitive to acids. Prolonged contact with concentrated solution may cause corrosion. For machines with aluminum boilers (often found in older models), it is better to use special soft agents or strictly adhere to low concentration (no more than 3-4%) and contact time.
Is it possible to add citric acid directly to coffee beans?
Absolutely not! Citric acid is intended only for flushing the hydraulic system. If acid gets into the grinder or brewing unit along with coffee, it will spoil the taste of the drink, possibly cause a chemical reaction with coffee oils, and damage the grinding mechanism.
Why did the car become noisier after cleaning?
If noise appears after cleaning, air may have entered the system, which needs to be vented by flushing water several times. The noise may also indicate that the acid has dissolved large pieces of scale that are stuck in the valves or pump. In this case, you may need to re-pressure wash or call for service.