The appearance of a characteristic humming sound when brewing coffee and a sharp decrease in the pressure of the exiting espresso stream indicate a critical build-up of scale in the hydraulic system. At this moment decalcification of coffee machine with citric acid becomes the only possible way to restore pressure in the system without expensive service intervention. Ignoring these symptoms leads to overheating heating element and failure of the pump, since limescale acts as a heat insulator, preventing heat from being removed from the heating element.
The use of citric acid is due to its ability to effectively dissolve calcium carbonate, which forms the basis of scale, without damaging the rubber seals and plastic tubes inside the device. Unlike aggressive chemicals based on hydrochloric acid, an aqueous solution citric acid It acts more gently, but requires adherence to precise dosage and temperature conditions. Violation of concentration can lead either to the ineffectiveness of the procedure or to excessive stress on the metal elements of the boiler.
The procedure for removing deposits requires a complete understanding of the design of your device, whether it is a horn model Gaggia, automatic device DeLonghi or capsule system DeLonghi Piccolo. Incorrect execution descaling can drive large particles of loose stone into the narrow channels of the brewing unit, causing mechanical blockage. Therefore, before starting active actions, it is necessary to study the washing algorithm and prepare distilled water for the final stages.
The mechanism of scale formation and the effect on the operation of the coffee machine
The main reason for the failure of heating devices is the hardness of tap water, which contains calcium and magnesium salts. When the liquid is heated above 60 degrees Celsius, these salts precipitate, forming solid deposits on the walls boiler and heating elements. A layer of scale just one millimeter thick can reduce heat transfer by 10-15%, causing electronics to increase heating time and consume more electricity.
Flow-through heaters are at greatest risk (thermoblocks), the channels of which have a small cross-section. Even a slight narrowing of the passage due to lime deposits creates resistance to the flow of water, which is recorded by pressure sensors as a “no water” or “blockage” error. In carob coffee machines with a boiler, scale often accumulates at the bottom of the tank and on the walls, from where, when boiling, it can enter the group, clogging the divider.
In addition to mechanical problems, limescale affects the taste of the drink, giving the coffee a metallic taste and reducing the brewing temperature. Descaling must be carried out regularly, since over time the deposits harden and turn into a monolithic crust, which is almost impossible to remove using household methods without disassembling the device. Regular maintenance prolongs service life pumps and maintains temperature stability.
⚠️ Attention: The use of acetic acid to decalcify modern coffee machines is strictly not recommended. Vinegar can be harsh on rubber gaskets and silicone tubing, causing them to dry out and lose elasticity, leading to leaks.
Necessary materials and solution preparation
To successfully carry out the procedure, you will need food-grade citric acid, which is sold in any grocery store in the form of crystalline powder or ready-made solution. A key success factor is the correct ratio of active substance and water, since a solution that is too concentrated can be overly aggressive for aluminum alloys often used in heat exchangers. The optimal concentration is considered to be not exceeding 4-5% for automatic machines and up to 8% for horn models with brass groups.
The water for preparing the solution should be soft, ideally distilled or passed through a reverse osmosis filter. Using hard tap water to prepare a decalcifier will reduce the effectiveness of the procedure, since some of the acid will immediately react with the salts in the water before reaching the walls of the boiler. Prepare in advance a container with a volume of at least 1.5 liters to collect waste liquid, since during the flushing process a significant volume of solution will pass through the system.
To work, you will also need a soft cloth, a syringe without a needle for cleaning hard-to-reach places and, possibly, a brush for the reservoir. If your coffee machine Saeco or Philips It has a removable brewing unit; it is better to remove it before starting the procedure in order to rinse it separately under running water. This will allow you to visually assess the condition of the seals and remove large fragments of coffee oil that could be mixed with scale.
- 🧪 Food grade citric acid (crystalline or solution).
- 💧 Distilled or filtered water for solution.
- 📏 Measuring glass or kitchen scale for accurate dosage.
- 🧽 Soft rags and a brush for cleaning the tank.
To achieve the best result, heat the water to dissolve the acid to 40-50 degrees, but do not boil it, so as not to speed up the reaction before starting the cleaning process.
Proportions and solution preparation table
Accurate adherence to proportions is a critical condition for the safety of the procedure. A solution that is too weak will not cope with deposits, and a solution that is too strong can damage the internal coatings. Below is a table of recommended concentrations for different types of coffee machines and degree of contamination.
| Coffee machine type | Water volume (ml) | Amount of acid (g) | Concentration (%) |
|---|---|---|---|
| Automatic (DeLonghi, Saeco) | 1000 | 30-40 | 3-4% |
| Carob (Gagggia, Rancilio) | 1000 | 50-60 | 5-6% |
| Capsule (Nespresso, Krups) | 500 | 15-20 | 3-4% |
| Heavy soiling (any type) | 1000 | 70-80 | 7-8% |
When calculating the amount of powder, keep in mind that 1 level teaspoon contains approximately 5-7 grams of citric acid. For a standard automatic coffee machine with a tank volume of 1.5-1.8 liters, 1.5-2 tablespoons of powder is usually sufficient. The crystals should be dissolved thoroughly until the sediment at the bottom completely disappears, so that large particles do not get into the pump.
You should not prepare the solution by eye, especially if you are performing the procedure for the first time. It is better to use a kitchen scale to measure the powder, as an error in dosage can cost expensive repairs. If you are using ready-made liquid citric acid concentrate, carefully read the instructions on the package, as its concentration may differ significantly from its powder counterpart.
Step-by-step instructions for decalcification
The descaling process begins with preparing the device: turn on the coffee machine and let it warm up to operating temperature, if the mode allows. Some models automatic coffee machines you need to enter the maintenance menu and select the “Descaling” or “Descaling” mode, which will put the device into a special algorithm for working with intermittent liquid supply. For carob models, simply fill the reservoir with the prepared solution and start passing it through the group.
Start the process of running the solution through the system. In automatic machines, this happens cyclically: the device draws water, heats it, supplies it to the group, pauses and repeats the cycle. It is important not to interrupt this process until the tank is empty. If you have a carob coffee maker, turn on the hot water supply or pour through the idle coffee horn, passing about 100-150 ml of solution, then turn off the machine for 10-15 minutes to allow the acid to act on the scale, then repeat the operation.
After the entire citric acid solution has been used up, it is necessary to thoroughly rinse the system with clean water. Pour fresh distilled water into the tank and run it through the coffee machine in the same mode as the acid solution. This procedure must be repeated 2-3 times to completely wash away the remaining acid and dissolved salts, otherwise the first brewed coffee will have a sour taste.
☑️ Decalcification checklist
Features of cleaning different types of coffee machines
Automatic coffee machines brands DeLonghi, Saeco and Philips often have a built-in decalcification program that must be activated. In models without a display, the process can be indicated through blinking LEDs in a certain sequence. It is important to strictly follow the algorithm, as the electronics control the volume of fluid passed and the temperature, ensuring maximum efficiency descaling.
Carob coffee machines such as Gaggia Classic or Lelit, require manual process control. It's important not to overheat here. heating element without water, so monitor the liquid level in the boiler. For machines with a stainless steel boiler, more concentrated solutions can be used, while for aluminum thermoblocks (often found in budget models), the concentration should be minimal to avoid corrosion.
Capsule machines (Nespresso, Dolce Gusto) have the most compact hydraulic system, so the risk of clogging is highest here. There are special cleaning modes for them, and the tank volume usually does not exceed 0.8-1 liters. When cleaning such devices, it is recommended to remove the container for used capsules and the drip tray so that the rinsing water flows freely out, taking with it dirt particles.
The secret of professionals
To enhance the effect, you can add a couple of drops of dishwashing detergent to the solution, but only if you are sure that you can rinse the system thoroughly, otherwise there will be foam in the coffee.
Common mistakes and precautions
One of the most common mistakes is using hot tap water to prepare the solution, which leads to instant precipitation of some of the salts even before the reaction with scale begins. Also, users often forget to flush the system with enough water, which leads to oxidation of metal parts and deterioration in the taste of coffee. Decalcification should be carried out in a well-ventilated area, although citric acid fumes are less dangerous than vinegar fumes.
Do not try to speed up the process by increasing the acid concentration beyond the recommended levels. This can lead to the destruction of the lubricant in the pump and damage to the rubber seals, which will require replacement of components. If the machine makes unusual sounds or leaks after cleaning, stop using it immediately and check the connections.
If the device has not been serviced for years, softened scale can fall off in large pieces and tightly clog narrow channels. In such cases, it is safer to contact a service center for mechanical or ultrasonic cleaning.
⚠️ Attention: Never leave the acid solution in the coffee machine boiler overnight or for a long time. Prolonged exposure to acid can lead to irreversible corrosion of metal parts and failure of solder joints.
Regular decalcification (once every 2-3 months) is much cheaper than replacing a boiler or pump, the cost of which can reach 50% of the price of a new coffee machine.
FAQ: Frequently asked questions
Can citric acid be used in coffee machines with a silver-coated boiler?
Silver nano coating (Silver Tech and analogues) in boilers DeLonghi and other brands are designed for antibacterial protection. Citric acid in recommended concentrations (up to 4-5%) does not damage this coating, however, the use of more aggressive acids (hydrochloric, acetic) is strictly prohibited, as they can destroy a thin layer of metal.
How often should decalcification be done with citric acid?
The frequency depends on the water hardness and intensity of use. On average, when using filtered water, the procedure is carried out once every 2-3 months or after every 200-300 cups prepared. If the water is very hard, the interval is reduced to 1-1.5 months. Monitor the indicator on the control panel, if provided by the manufacturer.
What should I do if there is an acidic taste in my coffee after cleaning?
This means that the system was not flushed well enough. It is necessary to repeat the rinsing cycle with clean water 1-2 more times. You can also brew 2-3 cups of coffee "empty" (without coffee or with cheap beans) to completely flush out the remaining solution from the brewing tract.
Is it possible to replace distilled water with boiled water?
Boiled water contains less salts than tap water, but is still not perfectly clean. To prepare a decalcifier solution, it is better to use distillate or water after a high-quality filter jug, so as not to introduce additional salts into the system during cleaning.