PREPARATION & TROUBLESHOOTING

Preparation and Troubleshooting: Frequently Asked Questions

There are no espresso laws. No espresso police. The only goal is a coffee that tastes good to you. Preparing espresso is like cooking at home: you experiment, use the spices and cookware you like, and cook the way you deem best. At the Coffee Coaching Club, we think about coffee from two perspectives: extraction chemistry and the biology of perception. This is our viewpoint, one of many. There is no ultimate opinion in the coffee world. Everyone has to find out for themselves what works. The only thing that matters: Does the coffee taste good or not?

Before you delve deeper: In our sensory world, you can use interactive simulators to try out for yourself how extraction and grind size affect the flavor profile. Playful, sensory, understandable.

How does the Coffee Coaching Club think about espresso preparation?

We don't measure time. We don't follow rigid recipes. We extract based on the ratio of ground coffee to extract. The standard ratio is 1:2, for example, 18g of ground coffee to 36g of espresso in the cup. But other ratios are also possible and can taste great, depending on the bean, roast, and your personal taste.

In our cafes in Bern and Zurich, we sometimes extract for up to 120 seconds. We grind very fine and extract slowly and steadily. This works because we use reliable coffee grinders that deliver a consistent grind and espresso machines with stable pumps and precise temperature control. At the same time, turbo shots with only 5 to 10 seconds of extraction time can taste fantastic, for example, with 100 percent Robusta beans. This is our way, but it is not the only one. Other roasters and baristas work with completely different methods and achieve great results. There is no right or wrong. There is only: Does it taste good to you?

Why doesn't my espresso taste the way I want it to?

There are two perspectives on this question. The first is extraction chemistry: What happens physically and chemically when hot water flows through ground coffee? The second is biology: How does your body perceive aromas and why do you perceive them the way you do?

On the chemical side: Coffee contains over 800 aroma compounds that dissolve at different stages of extraction. First, the fruity acids, then the sweetness and body, and finally the bitter compounds. If your espresso doesn't taste good to you, it almost always has to do with the ratio of these groups that end up in your cup. The variable you can most easily control: the ratio of ground coffee to extract and the grind size. Our Extraction Simulator shows you in real-time how every change affects the flavor profile.

On the biological side: Every person perceives aromas differently. Your genetics and your taste conditioning determine whether you find a coffee pleasant or unpleasant. This is not a defect, it is nature. There is no objectively perfect espresso, only your perfect espresso. What we describe here is our perspective. Others see it differently, and that is equally valid.

What does biology have to do with coffee enjoyment?

More than most people think. The perception of aromas is a biological process driven by survival. Your brain constantly evaluates: Is what I'm eating or drinking right now safe?

One example: Temperature. The hotter the espresso, the more your brain focuses on protecting the receptors on your tongue. Aroma perception takes a backseat because the brain prioritizes temperature information. That's why you taste less aroma but more body in hot coffee. If you let the same espresso cool down a bit, the aroma spectrum opens up because your brain lowers its protective function and forwards the aroma signals to consciousness.

The same principle applies to bitterness and sweetness. Your body has learned: Extremely bitter can be poisonous. If bitterness is too dominant, your brain suppresses sweetness perception at a neural level—even if the sweet compounds are still chemically present. If you reduce the bitterness, sweetness "appears" on its own. This is not taste education, it is neuroscience. In our Sensory 1×1, we explain these mechanisms in detail.

Furthermore, smell, audio-visual perception, and haptics play a role. The choice of vessel, its material, its color, its temperature influences how you perceive the coffee. An espresso from a thick-walled, preheated ceramic cup tastes different from the same espresso from a thin glass. Not because the coffee has changed chemically, but because your brain evaluates the overall situation differently. Sensory research calls this cross-modal perception—your brain combines all sensory impressions into a single taste image.

Can I replicate an espresso shot exactly?

No, and that's a good thing. You will never pull the same shot twice because you will never grind the same bean again. Every single bean is different: a different size, grown in a different part of the plant, thus slightly differently ripened. There are also minimal deviations during roasting. Not every bean in a batch is roasted exactly the same, which is physically impossible.

In addition, there are external factors that directly influence extraction. Humidity changes how the coffee grounds behave: On humid days, they swell more, the puck becomes denser, and extraction slows down. On dry days, the opposite is true. Temperature and air pressure also play a role. If you are very observant, you will notice differences between morning and afternoon, between summer and winter, between a rainy day and a sunny day.

And then there is the human factor. Your perception is constantly changing. You are never the same person you were yesterday. Your taste preferences evolve, your body changes, your mood influences how you perceive aromas. The weather, how well you slept, what you ate before, whether you are stressed or relaxed, all of this changes how the espresso tastes to you. The same shot, on the same day, with the same bean, can taste different at 8 am than at 3 pm.

Espresso extraction is complex, but not rocket science. There is no right and no wrong, only coffee that tastes good or doesn't. Everything you read here is our opinion, one of many in the coffee world. Find your own way. Let's just enjoy.

What influences the taste of my espresso the most?

From the perspective of extraction chemistry, there are some variables that have a particularly large influence:

The ratio of ground coffee to extract. Our standard is 1:2 (e.g., 18g in, 36g out). Shorter ratios like 1:1.5 result in a more concentrated, full-bodied shot. Longer ratios like 1:2.5 or 1:3 emphasize clarity and fruity notes. Experiment here first. In our Extraction Simulator, you can see the effects of different ratios directly.

The grind size. We tend to grind very fine and extract slowly and steadily. A finer grind size increases the contact surface between water and coffee and allows for more even extraction. This requires a grinder that delivers a consistent grind, from brands like Comandante, Varia, Mahlkönig, or Weber Workshops.

The brewing temperature. The higher the temperature, the more body you perceive. The lower the temperature, the more aroma and less body. At the same time, the body can make the aroma seem more harmonious. There is no right value, only the value that works for this bean and your taste.

The speed of the coffee grinder. Higher RPM tends to create more body in espresso, lower RPM emphasizes aroma. Grinders with variable speed or consciously low RPM from Option-O or Weber Workshops give you an additional adjustment screw here. Our Grinder Simulator shows you how RPM, burr type, and burr size affect the flavor profile.

The choice of basket. A different basket changes the espresso so fundamentally that it's like using a different bean. Hole size, hole distribution, and basket geometry influence the flow rate and thus which aroma groups are preferentially extracted. Experiment with different baskets from IMS or VST.

The puck screen. A fine metal screen on the coffee puck distributes the brewing water more evenly and reduces channeling. The result: less bitterness, more perceived sweetness. Thicker puck screens absorb more heat and significantly lower the effective brewing temperature, thin ones only slightly. In the Extraction Simulator, you can directly compare the difference with and without a puck screen.

These are the variables we consider particularly relevant. Other baristas prioritize differently, and that can also lead to the desired result. In the end, only one thing decides: Does the coffee in your cup taste good?

Why does my espresso feel thin, even though it has body?

This is one of the questions that has occupied us the most in recent months. The answer lies not in extraction chemistry, but in the biology of perception.

Your brain evaluates fullness not only through mouthfeel (physical viscosity) but combines it with retronasal aromas into a single impression. Sensory research calls this cross-modal perception. An espresso with high body but without sweetness and aromatic depth will be perceived as thin and watery—even though it is not physically thin. Conversely, an aromatically rich coffee feels fuller, even with the same viscosity.

This means: Body alone is not enough. Body without sweetness and aroma does not feel "full." That's why it's so important not only to optimize viscosity (grind finer, higher dose) but also to create the conditions for sweetness and aroma—even extraction, the right temperature range, a puck screen against channeling. In our Sensory 1×1, we explain the six taste dimensions and their couplings in detail.

Why is puck prep so important?

Puck prep is the preparation of the coffee puck in the portafilter before extraction. It is so crucial because it determines whether the water flows evenly through the coffee grounds or finds channels. Uneven flow means that one part of the coffee is over-extracted and another part is under-extracted. You taste both simultaneously, and that does not result in a clear, defined cup.

Our puck prep sequence: First, distribute the coffee grounds with a WDT tool (fine needles, moved circularly through the grounds) and break up clumps. Then create a smooth surface with a leveler. Finally, compact with a calibrated tamper. We prefer to work with tools from Normcore and Weber Workshops because they deliver reproducible results.

If you grind very fine and extract slowly, as we do in our roastery, clean puck prep becomes even more important. The finer the grind, the greater the risk of clumping and thus channeling. Good equipment for puck prep can be found in our Barista Equipment assortment.

Why do I need a good coffee grinder?

The coffee grinder is the most important piece of equipment in your setup, even more so than the espresso machine. At least, that's our conviction, and many in the coffee world share it. Others place the machine first, and that can also work. The reason for our stance: Consistent grind is a prerequisite for controlled extraction. If particle sizes scatter too widely, large particles will be underextracted and small ones overextracted, simultaneously, in the same shot. This results in an undefined taste that is neither clear nor harmonious.

In our roastery, we consciously grind very fine and extract slowly. This only works because our grinders deliver an extremely consistent grind. With a grinder that has a wide particle distribution, the same fine grind would clog the puck.

Another factor: the RPM of the grinder. Higher RPM tends to create more body, lower RPM emphasizes aroma. Grinders with slow-spinning burrs from Comandante (hand grinder), Option-O, or Weber Workshops offer a sensory advantage here. Electric all-rounders from Eureka, Mazzer, Fiorenzato, or Mahlkönig deliver reliable results in everyday use. For hand grinders, we also recommend Varia and Timemore.

Is there a best burr set?

No. Burr sets are like car engines: Each has its own character, and which one you like best is subjective. A flat burr set tends to produce a different flavor profile than a conical burr set. Within these categories, the results vary greatly again, depending on the geometry, material, coating, and size of the burrs.

Flat burrs often emphasize clarity and separation of aromas. Conical burrs tend to produce more body and a rounder cup. But these are tendencies, not laws. A large flat-burr grinder from Mahlkönig tastes fundamentally different from a smaller flat-burr grinder of the same brand. And a Comandante with conical burrs produces a completely different espresso than the conical burrs in a Varia hand grinder.

In addition, there are aftermarket burr sets like those from SSP, which can completely change the character of a grinder. It's like engine tuning: same grinder, different burrs, different coffee in the cup. There is no universally best burr set because it is subjective whether you like the flavor profile or not. Our Grinder Simulator shows you how burr type, grind geometry, RPM, and alignment affect the flavor profile—try the combinations and compare. And in our showrooms in Bern and Zurich, you can compare different grinders side-by-side and taste the difference directly in the cup.

How important is the design and haptics of coffee equipment?

More important than many think, and there's a real reason for that. Coffee doesn't begin with the first sip. Coffee begins the moment you look at your equipment, touch it, and start the process. Picking up the grinder, inserting the portafilter, pulling the lever. These are the moments when coffee is fun.

Whether you find your equipment beautiful, whether it feels good, whether the craftsmanship appeals to you, all of this influences your emotional state, even before the first drop of espresso falls into the cup. And your emotional state influences how you perceive the coffee. This is not esotericism, this is biology: Your brain does not evaluate enjoyment in isolation, but in the context of the entire experience.

That's why at the Coffee Coaching Club, we place great importance on offering equipment that is not only functionally convincing but also aesthetically and haptically pleasing. A grinder from Weber Workshops looks like a design object and feels like a precision instrument. A Flair Espresso has a ritual that makes the whole process deliberate and decelerated. A machine from Arkel is a statement in the kitchen, even before you turn it on. These are not trivialities. They are part of enjoying coffee.

Why do I need a good espresso machine?

The espresso machine must reliably deliver two things: stable temperature and consistent pump pressure. Both directly influence which aroma compounds are extracted from the coffee and in what balance they end up in your cup.

Temperature stability is crucial because even small fluctuations change the character of the espresso. Higher temperature emphasizes body, lower temperature emphasizes aroma. If the machine fluctuates during extraction, you get an unpredictable mixture. Dual boilers from La Marzocco or Arkel offer the highest precision here.

Pump stability is important because we extract slowly and steadily. If the pressure fluctuates, the flow rate through the puck changes, and the extraction becomes uneven. Machines with rotary pumps or high-quality vibratory pumps with pressure control provide the best results here. Note: These are the characteristics we prioritize for our brewing method. Those who work differently may need different equipment. The coffee in the cup decides, not the specification on the data sheet.

More on this in our Deep Dive on Heating Systems.

What kind of water should I use for espresso?

Water makes up over 90 percent of your espresso and has an enormous impact on taste and machine longevity. The mineral composition of the water determines which flavors are extracted from the coffee and how they taste in the cup.

Water that is too hard (lots of limescale) will scale up your machine and make the espresso flat and dull. Water that is too soft or distilled creates empty espresso because it lacks the minerals needed for extracting certain aroma groups. The ideal range is a total hardness of 50 to 100 mg/l. In Bern and Zurich, the tap water is significantly harder.

Your options: a water filter like systems from BWT or Brita, self-mixed water from distilled water and a mineral solution for full control, or mineralized bottled water with a suitable composition. We have a detailed guide on this: Composing your own coffee water.

How do I clean my portafilter machine correctly?

Regular cleaning is crucial for good taste and a long lifespan.

After each shot: Briefly rinse portafilter and basket under running water. Flush the group head with a short blank shot. Wipe the steam wand immediately after use with a damp cloth and briefly purge steam to prevent milk residue from drying.

Weekly: Backflush with cleaning detergent. Insert blind basket, add cleaning powder like Puly Caff, and start and stop the brewing process several times. Then repeat without detergent.

Don't forget the coffee grinder: Regularly clean the burrs and grinding chamber of old coffee grounds with a brush or blower. Old coffee grounds oxidize and impart rancid flavors to fresh grounds. Our cleaning assortment contains everything you need.

How do I prepare filter coffee correctly?

Filter coffee is the purest way to experience the aromas of a bean. Without pressure and with longer contact time, filter coffee particularly highlights the fine, floral, and fruity notes that sometimes disappear behind the body in espresso.

Here, too, our basic philosophy applies: there is no right or wrong. Experiment to find what you like. As a starting point: Use a medium to coarse grind (significantly coarser than espresso). A good starting ratio is 60 to 65 grams of coffee per liter of water. The water temperature is ideally between 92 and 96 degrees.

For pour-over methods like Hario V60 or Chemex: Start with a bloom (wet the coffee grounds with twice the amount of water and let it swell for 30 seconds), then pour in slow, circular motions. For French Press or AeroPress, other techniques and grind sizes apply. In our showrooms in Bern and Zurich, you can experience different filter methods and compare the differences directly in the cup.

Try it yourself: Our interactive simulators

Sometimes a slider says more than a thousand words. We have built two interactive tools in our Sensory World, based on the insights from our roastery. No video, no article — you move the parameters and immediately see what happens to body, sweetness, aroma, and bitterness.

The Extraction Simulator — Temperature, dose, ratio, grind size, and puck screen: how they change your flavor profile in real time. With context-dependent product recommendations.

The Grinder Simulator — Conical or flat? Classic or modern? How speed, burr size, and alignment determine particle distribution and thus taste.

The science behind the simulators can be found in the Sensory 1×1 — our glossary on body, sweetness, aroma, cross-modal perception, and neural suppression.

Further questions? Explore our other FAQ sections: Buying Guide | Brands and Products | Service and Shipping. Or dive directly into our Sensory World.