How does a capsule coffee maker work?

Do you want to know how a capsule coffee maker works? This type of coffee maker is so simple to operate for the user that we can make the mistake of thinking that its internal workings are just as simple. However, a capsule coffee maker works in much the same way as an espresso machine. In essence, we have a short packet of ground coffee, through which the coffee maker injects water at high pressure, which causes the drink to be poured immediately into our cup. The process is speedy and only takes a few seconds.

The fundamental difference with espresso machines is that in the latter, we must serve the ground coffee ourselves beforehand, either in the filter holder or in the grinder that these machines may have integrated. On the other hand, in capsule coffee machines, the coffee is already compacted inside the capsule, and we can’t determine its dose, its mixture, its pressing, or anything else. It’s all much more automatic.

We’ll say that the process seems simple, but if we look inside the coffee machines, we will see that the coffee machine has its complexity.

In this report, we want to show you how a capsule coffee maker works, which are the internal components that make it possible, and what function each of them has.

To begin with, and as a curiosity, here is the fantastic document that has served as a reference for the preparation of this article: the original Kraft Foods patent for the design of a Tassimo coffee maker, which dates from 2005.

capsule coffee maker inside

The drawing is very schematic but summarises what we will find if we open a capsule coffee machine and inspect, from the rear, its interior.

We will now briefly illustrate which parts are numbered so that you can better understand the drawing:

  • 225 is the boiler for heating the water.
  • 230 is the pump that takes the water from the tank and sends it to the boiler to be heated.
  • 220 is the water tank.
  • 235 is the air compressor.
  • 250 is the injection nozzle where the water comes out, goes through the capsule and is poured out.
  • 201 is the central control processor; in other words, it is the electronic component that ensures that all the other elements work in unison and in the right way.
  • Finally, the number 263 in the original drawing is simply an internal pipe designed for communication and water circulation inside the coffee machine.
dolce gusto inside

Components of a capsule coffee maker

Extrapolating that prehistoric Kraft design to our days, we can list the following essential components that any capsule coffee maker has:

  • A water reservoir. It usually varies between 0.6 litres and 1.5 litres of capacity. It is where we pour the water that will serve to prepare the coffee. (1)
  • A pump that makes the water circulate through the internal pipes of the coffee maker. The pump takes the water from the tank and sends it to the boiler. It then travels from the boiler to the outside. In a similar way to our organism, the pump would be the heart of our coffee machine. (2)
  • A boiler or water heating system If she didn’t get the coffees hot. In the capsule coffee machines, the most usual is to use the Thermoblock system. (3)
  • A pressure pump, located just before the water is injected into the capsule. It usually is 15 bar or 19 bar and is what causes the hot water to pass through the coffee in the capsule at high speed. (4)
  • An injector through which water comes out at high pressure. The nozzle pierces the capsule so that the water passes through the interior of the capsule and exits at the lower end of the capsule, joyfully converted into the coffee. (5)

And the final operating scheme of a capsule coffee maker, seen in the profile, is very similar to this other drawing:

schematic capsule coffee machine

In this scheme, steps (1) to (5) are those already explained in the previous paragraph. Those marked with the numbers (6) and (7) refer to serving the coffee from the capsule to the cup.

As you know, apart from this primary mode of operation, there are models of coffee makers that incorporate some additional elements, such as milk spraying tubes (as in the case of the Nespresso Lattissima) or specific compartments for storing milk (as in the case of the Senseo Latte Cappuccino). We will not detail them in this article because we consider that they are not part of the standard and basic functioning of a capsule coffee maker.

Distinctions: types of capsules

Although all capsule coffee makers work the same, each uses a different capsule system. Dolce Gusto has its capsules, Nespresso its own, Tassimo its own, Illy, Lavazza it’s all the same. And the capsules of one brand are not suitable for the coffee maker of another: they are of different sizes, different weights and sometimes unconventional methods for the coffee maker to recognise them. It is a disadvantage for the consumer, although it makes sense from the brands in this way, they secure the business and get people to buy their capsules by force.

Within each system, there are also compatible or refillable capsules, which are still exclusive to a particular firm (there are Dolce Gusto compatible capsules, compatible capsules for Nespresso, etc.) but which at least give the consumer the option of saving money or trying new varieties.

dolce gusto compatible nespresso capsules

In this image, the one on the right is a Dolce Gusto capsule, and the one on the left is a Nespresso capsule. The differences are apparent, don’t you think?

Maintenance and cleaning of capsule coffee makers

The essential maintenance of a capsule coffee maker is practically reduced to the periodic decalcification and general cleaning of both the tank and the nozzle that serves the coffee. It is one of the significant advantages of capsule coffee machines: they are usually cleaner and easier to maintain than others.

Decalcification is the most critical process, and you should carry it out from time to time. Its frequency depends on two factors: the use of your coffee machine and the hardness of the water you use. The more times you use your coffee maker a day, the more frequently you will have to decalcify it. And the harder the water you use to brew your coffee, too.

To give you an idea: in the best-case scenario (soft water and little use of the coffee maker), it will be enough to decalcify it every 18 or 24 months. On the other hand, if you use hard water and consume 3 or 4 capsules a day, then you should decalcify your coffee maker at least every three months.

Check out our descaling guides for more precise information about descaling coffee machines of a particular brand and our cleaning guides for valuable tips and tricks that will extend the life of your capsule coffee machine.

NOTE: For added safety, always refer to your machine’s instructions to know exactly when to start the decalcification process. Some coffee machines, such as the Tassimo, include a decalcifying alarm as standard, which automatically warns you when it is time to decalcify.

2 thoughts on “How does a capsule coffee maker work?”

  1. Our Dolce Gusto coffee machine does not do its first step of injecting water into the cup. Please advise how this can be fixed.


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