The question of whether it is possible to clean the coffee machine with citric acid, has been a fierce debate among owners of coffee equipment for many years. On the one hand, it is a cheap, affordable and natural remedy that is sold in any grocery store. On the other hand, manufacturers of professional and semi-professional equipment often explicitly prohibit their use in their operating manuals.
The root of the problem lies in the chemical reaction of acid with metals from which the hydraulic system of the device is made. While stainless-steelThe oxide used in many modern boilers is relatively inert to weak acids, and other components may be affected. This is especially true of aluminum alloys, brass fittings and, most critically, rubber seals and glands.
Our goal is not just to give the answer “yes” or “no”, but to weigh all the risks and explain the physicochemical processes that take place inside your body. DeLonghi, Saeco or Bosch. Understanding how acid affects different materials will help you make a smart decision and not make expensive repairs inevitable.
Chemical composition of scale and the principle of action of acid
Scale, or calcium deposition, is a solid precipitate formed when hard water is heated. The basis of these deposits are calcium and magnesium carbonates. Citric acid (2-hydroxypropane-1,2,3-tricarboxylic acid) is an organic tribasic carboxylic acid that reacts with hardness salts, turning them into soluble citrates.
The process of dissolution occurs due to the fact that hydrogen ions released by acid in an aqueous solution replace calcium ions in the scale structure. This leads to the destruction of the crystal lattice of the sediment. However, the effectiveness of this process depends on the concentration of the solution and the temperature at which the reaction takes place.
The problem is that the reaction is not selective only with respect to scale. The acid does not “understand” where the harmful plaque ends and the useful metal or rubber seal begins. If the concentration is too high, the aggressive environment will begin to affect the structural elements of the coffee machine.
⚠️ Caution: Using too concentrated citric acid solution can lead to irreversible damage to internal tubes and heating elements. Keep your proportions!
Unlike specialized products that often contain corrosion inhibitors, pure citric acid has no protective additives. These inhibitors in occupational chemistry allow the acid to dissolve scale, but slow or stop the reaction with the metal, protecting the equipment.
The effect of citric acid on materials of the coffee machine
To understand the degree of risk, it is necessary to consider the materials from which the internal nodes of coffee makers are made. Most modern models are a complex composite of various metals and polymers.
Aluminum and its alloys are often used in heat exchangers and some types of boilers in the budget segment. Citric acid reacts actively with aluminum, causing its corrosion. This can lead to microcracks through which water will begin to enter the electrical part or mix with oil in the gearbox.
Brass used in fittings and valves is more stable, but with prolonged exposure to acid, zinc can be washed out of the alloy (decincification). This weakens the mechanical strength of the parts and can lead to leaks under high pressure.
Rubber seals, gaskets and gums are the Achilles heel of any coffee machine when using aggressive chemistry. Acid makes rubber hard, brittle or, conversely, too soft and loose. As a result, the tightness of the system is violated.
How to determine the material of the boiler?
If you do not have technical documentation, the weight of the car and the price can be an indirect sign. Aluminum boilers are more common in light and inexpensive models. The exact answer will give only a service book or a call to the manufacturer.
Nevertheless, stainless-steel (Mark 304 or 316), used in boilers of many devices, is quite resistant to short-term exposure to solutions of citric acid. That is why many users have been using this method for years without any visible consequences, even without realizing the risks to other nodes.
Comparison of citric acid and specialized products
The market offers a variety of solutions for scale removal, from bags with “lemon” to expensive branded liquids. What is the difference between them and should they be overpaid?
Specialized tools are developed by engineers specifically for the working conditions of coffee machines. They take into account boiling point, system pressure and compatibility with all materials. The main advantage is the availability corrosion inhibitors and lubricating components for sealants.
Citric acid is a mono-component. It performs one function (acid), but does not protect. In addition, in the powder from the store there may be impurities that, when dissolved, precipitate or foam, which is dangerous for the pump.
Dosage is also an important aspect. The bag with the chemicals from the manufacturer has already met the ideal proportions. When using citric acid, you act at random: underwhelm - do not clean, overdo - spoil the equipment.
Below is a table comparing the key characteristics of both cleaning methods:
| Parameter | Citric acid | Specialized equipment | Acetic acid |
|---|---|---|---|
| Cycle price | Very low. | Tall. | Low. |
| Safety for aluminum | Low. | High (depending on composition) | Critically low |
| Protection of sealants | Absent. | Present. | Destroys rubber. |
| Taste after flushing | Maybe it's still a taste. | Neutral. | Persistent smell of vinegar |
Step by step: how to safely decalcinate
If you still decide to use citric acid, strict adherence to the process technology will help minimize the risks. Do not use concentrated powder by pouring it directly into the tank.
First, you need to prepare a solution of the correct concentration. The optimal proportion is 10-20 grams of powder (about 1 teaspoon without a slide) per 1 liter of water. The water must be warm but not boiling so that the acid dissolves completely.
☑️ Checklist before launching decalcination
Pour the resulting solution into a water tank. Turn on the coffee machine and start the process of running water through the system. If you're in your model Saeco or Philips There is a “Decalcify” mode, use it. If not, simply turn on a hot water supply or a coffee-free beverage by spilling the solution through the group.
It is important not to let the solution stagnate inside the heating element for a long time, if the instructions to your device do not require this. Circulation is more important than reaction time. After running the entire volume of the tank, be sure to perform 2-3 cycles of washing with clean water to wash the residues of acid and dissolved scale.
⚠️ Warning: If during cleaning you hear an unusual pump noise or smell burning, immediately stop the process, turn off the device from the network and contact the service.
Typical mistakes and myths about cleaning
There are many misconceptions that can lead to breakdown of the technique. One of the most common myths is that “natural means safe.” It is not: concentrated citric acid is a reagent that requires careful handling.
Another mistake is the use of acetic acid. Vinegar is much more aggressive than the lemon counterpart, has a persistent odor that is almost impossible to wash out of the system, and is strictly prohibited by manufacturers for most models due to the high risk of corrosion and damage to plastic tubes.
It is also a mistake to think that cleaning is necessary only when the machine has stopped heating or supplying water. Preventive cleaning It should be carried out regularly, according to the manufacturer's recommendations (usually every 2-3 months or after a certain number of brewing cycles). Remove a thick crust of scale is much more difficult and dangerous than regularly washing off a thin plaque.
To check the hardness of water, use special test strips. If the water is soft (up to 2 dH), frequent decalcification is not required, which will prolong the life of your car.
Some users try to amplify the effect by adding soda or other components. This cannot be done, as an unpredictable chemical reaction can lead to foaming of the solution inside the narrow channels and water shock.
When you can not use acid
There are situations where experiments with home chemistry should be excluded completely. First of all, this applies to coffee machines with boilers made of aluminum or its alloys. If the instruction says “Use only brand X descaler” in black and white, ignoring this requirement will void the warranty.
Also, you should refrain from using acid if you notice that the machine has already begun to “glutch”: the temperature jumps, leaks appear or a knock is heard. Introducing an aggressive environment into a worn-out system can be the last straw.
Professional models with direct connection to the water supply often have built-in softening systems or require specific reagents. Using an inappropriate acid can clog filters or damage electronic fluid level sensors.
⚠️ Note: The use of non-original decalcination products during the warranty period is a legal ground for refusing free repairs by the manufacturer.
Owners of carob coffee makers with brass groups (for example, some models) Lelit or Quickmill) should be particularly careful. Brass requires careful treatment, and frequent acid washing can lead to oxidation of the metal and change the taste of espresso.
The main risk of using citric acid is not instant breakage, but accelerated aging of rubber seals and microscopic corrosion, which will manifest itself after a year or two of active operation.
Frequently Asked Questions (FAQ)
How many grams of citric acid do you need per 1 liter of water?
The optimal proportion is 10-15 grams (about one teaspoon without a large slide) per 1 liter of water. Excess concentration will not speed up the process, but will increase the risk of damage to parts.
Can I clean citric acid capsule coffee machines?
Manufacturers of capsule systems (Nespresso, Krups) strongly recommend using only their branded products. The internal tubes in such machines are very thin, and the risk of damage or clogging with undissolved particles is high.
How often should decalcification be performed?
The frequency depends on the hardness of the water and the intensity of use. On average, once every 2-3 months or after preparing 200-300 cups. If the water is very hard, the interval is reduced.
Will the taste of lemons remain in the coffee after cleaning?
With thorough washing (2-3 full tanks of clean water), the taste disappears. If the taste of the acid is preserved, then the solution was too concentrated or washing was not carried out with high quality.
Is citric acid harmful to health if its residues get into the drink?
Citric acid is a dietary supplement (E330) and in small amounts is safe for humans. However, the ingestion of reaction products (calcium citrates) and excess acid can spoil the taste of the drink.