For many, coffee is more than just a beverage: it's a morning pick-me-up, a moment of pure enjoyment, and for some, even a passion. But while high-quality beans, expensive machines, and the right brewing method are often the focus, the small details are easily overlooked. Yet, even a tiny mistake in coffee preparation can noticeably alter the result.
Perhaps this has happened to you before: You buy freshly roasted coffee, brew it at home – and yet it tastes bitter, too acidic, or simply bland. This is often not due to the beans themselves, but to avoidable brewing mistakes. The good news: These mistakes are easy to identify and can be corrected with just a few simple steps.
In this guide, we'll look at the 5 most common mistakes in coffee preparation , explain why they occur, how they affect the taste, and – most importantly – how you can avoid these mistakes , whether you prefer espresso, filter coffee, or French press.
1. Incorrect grind size
The grind size is key to a successful extraction. It determines how long the water is in contact with the coffee grounds and how many flavor compounds are extracted. Even small variations can make the difference between a perfect cup and a ruined coffee.
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Ground too coarsely : The water rushes through too quickly or flows off too easily. The coffee is underextracted, meaning not enough flavors have been extracted. Typical result: thin body, flat flavors, often unpleasantly acidic.
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Ground too finely : The water takes far too long to penetrate or even clots. This leads to over-extraction of the coffee – bitter substances and tannins dominate. The result: unpleasantly bitter, a fuzzy feeling on the tongue, with hardly any sweetness or fruitiness.
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Why is this important?
Extraction is like a balance. Ideally, sweetness, acidity, and body dissolve harmoniously. A grind that is too coarse or too fine throws this balance off.
How do you avoid this mistake?
- Adjust the grind size precisely to the brewing method: coarse (like sea salt) for French press, medium (like sand) for filter, very fine (almost like flour) for espresso.
- Make sure you don't use a cheap blade grinder – it cuts the beans unevenly. A good grinder with a burr or conical burr grinder produces a consistent grind, which is crucial for extraction.
- Test and adjust: If the espresso flows too quickly, grind finer. If it drips too slowly, grind coarser. The same applies to filter coffee – if it's too weak, grind finer; if it's bitter, grind coarser.
2. Incorrect water and temperature
Many people pay attention to the beans and machines, but not to the water – yet a cup of coffee consists of over 98% water. Therefore, errors in water quality or temperature are among the most common mistakes in coffee preparation .
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Hard water : Contains a lot of limescale (calcium, magnesium). This accentuates bitter notes, makes the coffee taste dull, and leads to faster limescale buildup in your machine.
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Water that is too soft contains hardly any minerals. The result is a flat, uncomplex taste, since minerals are crucial for extraction.
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Water that is too hot : Above 96°C, coffee begins to burn. Aromatic compounds are destroyed, and bitterness dominates.
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Water that's too cold : Below 90°C, it doesn't extract enough water. The coffee tastes sour, weak, and unbalanced.
Why is this important?
Minerals in the water bind flavor compounds, so they are necessary to fully extract the taste. At the same time, the temperature determines whether the extraction process is complete and harmonious.
How do you avoid this mistake?
- Use filtered water with medium hardness (approx. 6–8 °dH). Filter jugs or special cartridges help to optimize tap water.
- Pay attention to the brewing temperature: 92–96 °C is ideal. This is shortly after boiling, when the water is no longer boiling but has cooled slightly.
- A kettle with temperature control is a worthwhile investment for consistently good coffee.
3. Unclean equipment
Even the best water and the freshest beans are useless if your equipment isn't clean. Many underestimate this point – but old coffee oils, limescale, and milk residue are among the most common mistakes in coffee preparation . They act like foreign flavors and mask the true quality of the beans.
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Coffee fats and oils : These remain in the machine, pot, or filter after each use. Over time, they oxidize and develop rancid notes, significantly altering the taste.
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Milk residue : Deposits tend to accumulate quickly, especially around steam nozzles. These can be unhygienic and also create unpleasant tastes.
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Limescale deposits : These are caused by hard water. They build up in pipes and heating systems, altering the brewing temperature and causing your coffee to taste inconsistent.
Why is this important?
Cleanliness determines the purity of the taste. When you buy a high-quality specialty coffee, you should taste it as it was intended – without any distracting aftertaste from the machine.
How do you avoid this mistake?
- Rinse jugs, filters and portafilters thoroughly with hot water after each preparation.
- Descale your machine regularly, especially if you have hard water.
- Use espresso machine cleaner or special powders to remove coffee oils from filters and brewing groups.
- Clean steam nozzles immediately after each use, before milk residue dries out.
4. Incorrect coffee-to-water ratio
A classic among the most common mistakes in coffee preparation is incorrect dosage. Many beginners measure by feel or with an included spoon. This quickly leads to coffee that is sometimes too strong and sometimes too weak – even with the same beans.
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Too little coffee : The water "washes" through the grounds, the extraction is too weak. Result: watery, flat taste, hardly any body.
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Too much coffee : The balance is disrupted, the coffee tastes overloaded, over-extracted, often bitter and unpleasantly strong.
Why is this important?
The correct ratio ensures that all aromatic compounds are extracted in a balanced way. Too little coffee prevents complete extraction, while too much leads to an overconcentration of bitter substances.
How do you avoid this mistake?
- Use a scale instead of a measuring spoon. Even a few grams difference can change the taste.
- Stick to the basic rule: 60 g of coffee per 1 liter of water . This corresponds to approximately 15 g in 250 ml of water (a normal cup).
- Adjust the ratio slightly to suit your taste – a little more coffee for strong espresso, a little less for lighter filter coffee.
- Work with recipes that clearly specify the grind size, quantity, and brew ratio whenever possible.
- With this small change, you will immediately achieve more consistent results.
5. Bad or old beans
Even the best technique is useless if the raw materials aren't right. One of the most serious, yet easily avoidable , mistakes in coffee preparation is using bad or old beans.
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Industrially roasted coffee : It is often stored for months before it ends up on the supermarket shelf. The aroma has usually already largely dissipated.
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Old beans : Coffee is a natural product and loses significant intensity just a few weeks after roasting.
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Incorrect storage : Open packages, light, air and moisture cause coffee to age faster and lead to a stale taste.
Why is this important?
The quality of the bean is the foundation of every cup. You can optimize a lot with water, grinder, and preparation – but if the bean is old or of inferior quality, you will never achieve a good result.
How do you avoid this mistake?
- Buy coffee as fresh as possible from local roasters or directly online from specialist roasters.
- Pay attention to the roasting date, not just the best-before date. Ideally, use within 6–8 weeks of roasting.
- Store the coffee in an airtight container in a cool, dark place.
- Avoid the refrigerator or freezer – coffee quickly absorbs foreign odors there and loses its aroma.
- Always grind the beans just before preparation, as ground coffee loses its aroma within minutes.
- Fresh, high-quality beans are the foundation – without them, all efforts in preparation are wasted.
Conclusion: Avoid mistakes, enjoy better coffee
The most common mistakes in coffee preparation aren't major mishaps, but rather small oversights that have a noticeable impact on the final product. A grind that's too coarse, the wrong type of water, unclean equipment, incorrect dosage, or old beans – all of these can ruin even good coffee.
The beauty of it is that these mistakes are easily avoidable. Simply paying attention to five key points – grind size, water quality, cleanliness, ratio, and bean freshness – will noticeably improve your coffee. You don't need a high-end machine or exotic beans: what matters is mastering the basics.
Avoiding these mistakes in coffee preparation will give you a completely new coffee experience. Suddenly, espresso no longer tastes bitter, filter coffee no longer weak – but full-bodied, balanced, and aromatic.
For beginners, this means you can easily achieve results at home that come close to café quality. And the better you master the basics, the easier it will be to experiment later with different roasts, preparation methods, or brewing recipes.
In short: Anyone who knows and avoids the most common mistakes in coffee preparation always holds the key to good coffee – whether espresso, filter or French press.
Image source: Jakob Owens via Unsplash
Avoid the 5 most common mistakes in coffee preparation - a guide for coffee beginners
For many, coffee is more than just a beverage: it's a morning pick-me-up, a moment of pure enjoyment, and for some, even a passion. But while high-quality beans, expensive machines, and the right brewing method are often the focus, the small details are easily overlooked. Yet, even a tiny mistake in coffee preparation can noticeably alter the result.
Perhaps this has happened to you before: You buy freshly roasted coffee, brew it at home – and yet it tastes bitter, too acidic, or simply bland. This is often not due to the beans themselves, but to avoidable brewing mistakes. The good news: These mistakes are easy to identify and can be corrected with just a few simple steps.
In this guide, we'll look at the 5 most common mistakes in coffee preparation , explain why they occur, how they affect the taste, and – most importantly – how you can avoid these mistakes , whether you prefer espresso, filter coffee, or French press.
1. Incorrect grind size
The grind size is key to a successful extraction. It determines how long the water is in contact with the coffee grounds and how many flavor compounds are extracted. Even small variations can make the difference between a perfect cup and a ruined coffee.
Extraction is like a balance. Ideally, sweetness, acidity, and body dissolve harmoniously. A grind that is too coarse or too fine throws this balance off.
How do you avoid this mistake?
2. Incorrect water and temperature
Many people pay attention to the beans and machines, but not to the water – yet a cup of coffee consists of over 98% water. Therefore, errors in water quality or temperature are among the most common mistakes in coffee preparation .
Why is this important?
Minerals in the water bind flavor compounds, so they are necessary to fully extract the taste. At the same time, the temperature determines whether the extraction process is complete and harmonious.
How do you avoid this mistake?
3. Unclean equipment
Even the best water and the freshest beans are useless if your equipment isn't clean. Many underestimate this point – but old coffee oils, limescale, and milk residue are among the most common mistakes in coffee preparation . They act like foreign flavors and mask the true quality of the beans.
Why is this important?
Cleanliness determines the purity of the taste. When you buy a high-quality specialty coffee, you should taste it as it was intended – without any distracting aftertaste from the machine.
How do you avoid this mistake?
4. Incorrect coffee-to-water ratio
A classic among the most common mistakes in coffee preparation is incorrect dosage. Many beginners measure by feel or with an included spoon. This quickly leads to coffee that is sometimes too strong and sometimes too weak – even with the same beans.
Why is this important?
The correct ratio ensures that all aromatic compounds are extracted in a balanced way. Too little coffee prevents complete extraction, while too much leads to an overconcentration of bitter substances.
How do you avoid this mistake?
5. Bad or old beans
Even the best technique is useless if the raw materials aren't right. One of the most serious, yet easily avoidable , mistakes in coffee preparation is using bad or old beans.
Industrially roasted coffee : It is often stored for months before it ends up on the supermarket shelf. The aroma has usually already largely dissipated.
Old beans : Coffee is a natural product and loses significant intensity just a few weeks after roasting.
Incorrect storage : Open packages, light, air and moisture cause coffee to age faster and lead to a stale taste.
Why is this important?
The quality of the bean is the foundation of every cup. You can optimize a lot with water, grinder, and preparation – but if the bean is old or of inferior quality, you will never achieve a good result.
How do you avoid this mistake?
Conclusion: Avoid mistakes, enjoy better coffee
The most common mistakes in coffee preparation aren't major mishaps, but rather small oversights that have a noticeable impact on the final product. A grind that's too coarse, the wrong type of water, unclean equipment, incorrect dosage, or old beans – all of these can ruin even good coffee.
The beauty of it is that these mistakes are easily avoidable. Simply paying attention to five key points – grind size, water quality, cleanliness, ratio, and bean freshness – will noticeably improve your coffee. You don't need a high-end machine or exotic beans: what matters is mastering the basics.
Avoiding these mistakes in coffee preparation will give you a completely new coffee experience. Suddenly, espresso no longer tastes bitter, filter coffee no longer weak – but full-bodied, balanced, and aromatic.
For beginners, this means you can easily achieve results at home that come close to café quality. And the better you master the basics, the easier it will be to experiment later with different roasts, preparation methods, or brewing recipes.
In short: Anyone who knows and avoids the most common mistakes in coffee preparation always holds the key to good coffee – whether espresso, filter or French press.
Image source: Jakob Owens via Unsplash