Coffee Knowledge Base

05 March 2024

How to brew espresso in the correct way?

How to brew espresso in the correct way?

How to brew espresso in the correct way? That is something we would like to talk about in this blog. Before we begin, let’s make it clear that brewing espresso could be the subject of an entire book. So, it is not our intention to provide a detailed instruction manual here. But we are happy to recommend you to read literature on the subject, e.g. the book titled The Home Barista. We will stick simply to the basics here.

Let’s start with the following question. ‘Why do we, in Central and Northern Europe, drink so little espresso?’ The answer is simple and unambiguous. It is because 98% of the espressos served in this part of the world are brewed incorrectly and therefore don’t taste the way they should. When making an espresso – just like with filter coffee – we always strive for the perfect balance between acidity, sweetness and bitterness. You achieve that perfect balance by preventing any one of those factors dominating the flavour. Of course, when brewing any type of coffee, you always have to consider its origin and the resulting intrinsic characteristics.

It is true that – unlike brewing filter coffee – you can only make a good espresso with a decent (that is, not cheap) machine, which is made to serve far more than one cup per day and is perfectly maintained. Given the small number of coffees that you usually prepare at home, you will most probably make many bad espressos and waste a lot of beans before you achieve an acceptable result. That is precisely why this blog is not compiled from the perspective of the home user, and it is merely written with the intention of describing how to brew espresso in the correct way.


To make a delicious espresso, you need more than good coffee and a good barista – the brewing materials must be of professional quality too. And it is essential that the materials (equipment) are properly maintained and cleaned.

The grinder

Real coffee fans will have undoubtedly already invested in an expensive espresso machine. But have you ever considered the importance of the grinder? Probably not, and yet the grinder is very important for making good espresso. I like to compare it to a car. The espresso machine is the car and the grinder is the refinery that makes its fuel. If the petrol is poorly refined, even the most beautiful sports car will not run well. The same applies when brewing coffee. Without a good grinder and the necessary know-how for adjusting it to suit your espresso machine, you will not achieve good results.

We grind coffee beans so that they will release their flavours. The way they are ground, the degree of grind, its consistency and other factors have a huge impact on the rest of what you do. The grinding discs must be clean and sharp, to avoid an unevenly ground result, which you will notice in the cup right away – it will make an unbalanced coffee that you would rather not drink.

The hopper, or container on top of the grinder in which the beans are stored for grinding, must be thoroughly cleaned weekly to prevent oils from sticking onto its walls and contaminating the fresh beans, which will be used for the next cups of coffee. This is another factor detrimentally affecting the flavour and balance of an espresso.

The espresso machine

Of course, espresso machines come in all sorts of styles, colours and different price ranges. As a general rule, you can categorize them into three groups: manual, semiautomatic and fully automatic.

Just as the name suggests, a manual machine is operated by hand. This machine requires an operator or barista who handles each task, from grinding and tamping to making the coffee.

The fully automatic machine does all this by itself. As soon as the user presses the button, it grinds a portion of coffee, tamps it and makes the espresso. The great advantage of this machine is, of course, that you do not need to invest in a barista. He or she is actually replaced by the machine. It also has the advantage of guaranteeing consistent quality, but when it comes to a supreme cup of espresso, this type of machine will never make one.

Semi-automatic machines are generally used in coffee bars and offer the barista the freedom to add his or her touch to the coffee. In these machines, the pump, the boiler and the temperature are automatically controlled. All the other factors depend on the barista, who decides, for example, how long or short the flow-through time should be for a shot of espresso.

Should it have a single or double boiler system?

Espresso machines are available with single or double boiler systems. Making this choice depends entirely on the intended use of the machine. Compare it with buying a car. If you want to race on a circuit, a Ferrari could be a great option. But if you are looking for a car to take the children to school every day, then a simple family car will do the job better. The choice of an espresso machine is no different. Do you need a high hot-water and steam discharge rate? Do you want to make shots while also steaming milk? If so, choose a double boiler, because you will have guaranteed optimal temperature control on the machine and its capacity will be much greater. If your requirements are only something simpler, a single boiler will suffice.

Daily maintenance

Each and every day, an espresso machine must be cleaned thoroughly. The specific method of cleaning might vary slightly for each machine but regardless of the type, keeping a clean and well-maintained espresso machine is an essential weapon against disastrous coffee experiences.

Coffee contains oils that deposit on surfaces. These oils become rancid and it is better to avoid having them in your cup of coffee. A daily cleaning procedure does not simply contribute to tasty coffee, it extends the working life of the machine too.


A cup of coffee consists of 98% water. So choosing good-quality water is not an insignificant factor. In many countries, tap water can vary considerably, depending on the location. So make sure your water is treated in such a way that lime and other minerals are kept under control.

Other supplies

  • A tamper: to press the coffee firmly and evenly in the filter holder.
  • Dregs container (or dregs drawer): to beat the used coffee into.
  • Milk jugs: for steaming milk into.
  • Hard brush: a useful tool for cleaning the group head.
  • Thermometer: for checking the milk temperature when steaming.
  • Cleaning cloths: essential for maintaining cleanliness on and around the machine.
  • Cleaning product: for cleaning the machine daily
  • Scale: for weighing the coffee.


Drinking espresso

To make a balanced espresso, it is important to know how an espresso is assessed and how it is made up. And how do you actually drink an espresso? That seems like a simple question, but the answer is not as obvious as you would think.

An espresso is made by tamping about 20 grams of very finely ground coffee in a filter holder and then pushing hot water through it under pressure. The result is 20 to 30 ml of coffee, which consists of a black, liquid mass with a thick, deep brown to reddish creamy layer or ‘crema’ with good elasticity.

The crema – and this is important – is simply the collection of oils and undissolved particles from the coffee. The crema contains the bitter substances that play an essential role in making up the flavour balance of the cup of espresso.

A common and significant mistake that people make is to drink an espresso immediately after it is brewed. When you do this, you first taste only the crema and that will certainly be a bitter experience. It is therefore important to first roll the espresso around the cup or stir it, so that you do not drink it in layers but as a complete drink. Mixing the different parts of the coffee before drinking it gives you a correct balanced experience. An espresso should be syrupy like hot honey. It should be quite thick in structure and have a nice thick, deep brown-reddish crema on the surface.

Brewing espresso

Unlike filter coffee, where gravity generally handles the task, extraction here is achieved by pushing pressurized hot water through the coffee grounds. That level of pressure does something that gravity could not do; it extracts the oils, sugars and fats from the coffee. That creates the characteristic intense and complex flavour and the thick, velvety structure of an espresso. As we said earlier, a detailed explanation about brewing espressos is not within the scope of this blog, but here are a few basic rules:


  • The temperature of an espresso machine must be 92 to 93 °C.
  • The portafilter must be cleaned with a dry cloth. Not only to remove old coffee residues, but also to ensure a dry start. If the portafilter is wet, then the water will be attracted to its wet sides and will not extract evenly through the entire coffee bed.
  • Grind the coffee and fill the portafilter. Make sure your grinder is correctly adjusted (see adjusting the grinder, p.188).
  • Level the coffee with your thumb and forefinger to avoid a little tower of ground coffee. This also ensures that the coffee is evenly distributed in the portafilter.
  • Wipe the edges of the portafilter with your thumb and forefinger so that no ground coffee remains. Any residue will prevent the filter holder sealing perfectly in the group head. Now tamp the coffee evenly to ensure nicely even horizontal distribution of the water’s passage through the ground coffee (i.e. so that it does not all run through in one area that is less compact).
  • You must rinse off the group head before putting the portafilter with the freshly ground coffee in it. This washes away any coffee residues from the previous cup. If you look at the head of the group before rinsing, you will see that it is full of coffee residue.
  • Clean the tray on which you place the cups to avoid making the bottom dirty before you serve it.
  • Put the portafilter in the group head and press the button immediately. It is extremely important to do this right away as it prevents the coffee from becoming bitter.
  • Place the cup under the filter outlet.
  • Watch the two streams. They must flow in three phases. Firstly, they must be thin and dark brown like melted chocolate. Then the two streams become wider and the colour becomes a little lighter (dark and honey-like). Stop as soon as the stream becomes clear and watery. At that moment all the positive flavours have been extracted from the coffee. Going further will not add anything positive to the cup of espresso.
  • The espresso should have run into the cup for about 23 to 30 seconds from the moment the button is pressed. The volume in the cup will be between 20 and 30 ml, depending on the intensity that you prefer.
  • Roll the cup and stir the espresso gently with a spoon before drinking it.


Grinder adjustment

The grinder can greatly affect the quality of a shot of espresso. This factor is all too often underestimated. How the beans are ground has a major influence on the flow-through time of an espresso. If the coffee is ground too coarse, the hot water flows through too fast and it can’t fully extract the flavours. As you would expect, this results in an underdeveloped and sour espresso with negative characteristics. But if it is ground too fine, the flow-through time is too long and the result is an over-extracted and bitter espresso. If you notice that the flow-through time is not between 23 and 30 seconds, adjusting the grinder is an absolute necessity.

Troubleshooting when the flow-through time is too short: Check the ‘coffee biscuit’. This is the name for the ‘cake’ of coffee grounds (the dregs) remaining in the portafilter after making the espresso. If the brewing method is just right, it forms a nice biscuit or cake. If the biscuit is wet and sloppy, you have insufficient volume of coffee in the portafilter. If this is the case, increase the weight of ground coffee you use. If the biscuit is dry and the portafilter is already full, you can’t increase the weight any more. So you need to grind the coffee finer. Grinding the coffee finer makes the same volume more compact, which slows the passage of water and increases the flow-through time.

Troubleshooting when the flow-through time is too long: In this case, you have either used too much coffee or it is ground too finely. Check the biscuit again. If it is wet, the coffee is ground too finely and you can set the grinder coarser. That way you make a greater volume but the coarser grounds allow the water to flow through faster. If the biscuit is dry and the portafilter is fully filled, use a little less coffee.

Espresso troubleshooting



  • Modify only one factor at a time. Do not change the weight and the degree of grind at the same time, because it will lead to hopeless confusion.
  • If you change the weight, the result is immediately detectable in the next coffee. But if you adjust the degree of grind, you should be aware that there will still be some ground coffee from the last batch between the grinder blades. In this case, you will have to make a few coffees before the result of adjusting the degree of grind is clear.
  • Make sure the hopper of your grinder is at least twothirds full. If it is not, the grinder will grind an insufficient volume each time because there is insufficient weight in the hopper.
  • Taste. Taste. Taste. The most important thing is that you taste the result and assess it.

Why use a double portafilter?

Every espresso machine is delivered with a single and a double portafilter when new. The single one is intended for brewing one espresso. The double spout is for brewing two espressos at once or a double espresso. However, it is impossible to use both portafilters to brew exactly the same espresso. The difference is caused by the structure of the filter holder and the distribution of the ground coffee in it.

A single filter holder has bevelled edges slanting towards its centre. This concentrates the coffee in the centre. But a double filter holder has edges running straight downwards and the water flows perpendicularly downwards, distributing evenly through the coffee bed. In other words, the way the water moves through the coffee bed is completely different. And besides that, all the water in a double filter holder flows though the double portion of coffee. The extraction degree is therefore much greater and more penetrating than with a single holder. An espresso brewed with a single filter holder therefore tastes a lot less intense. That is why professional baristas exclusively use double portafilters.

Assessing flavour

As we said earlier, when assessing an espresso, we are looking for the ideal flavour balance between acidity, sweetness and bitterness. And, of course, you have to consider the characteristics of the bean used. Tasting is very important. If you are not satisfied with the result, run through this checklist.

Flavour too sour


  • Flow-through time too short – see above under grinder adjustment.
  • Water temperature too low – the water temperature must be constantly between 92 and 93 °C.
  • Cold portafilter – check whether the portafilter is warm enough at the start. Leave the portafilter in the group head or put upside down on top of the machine so that it stays warm.

Excessively bitter flavour


  • Flow-through time too long – see above under grinder adjustment.
  • Water temperature too high – if the temperature is higher than 93 °C, there is a risk that the coffee will burn, which releases bitter substances.
  • Dirty machine  make sure the machine is clean. Have the heads of the group been rinsed and cleaned? Are the portafilters cleaned properly every day?
  • Old beans  check the roasting date of the coffee beans. Ideally, coffee beans should be used within a month of the roasting date.