Almost every coffee drinker has experienced it: the coffee suddenly tastes unpleasantly bitter, aggressive, or "burnt." But what causes this?
While bitterness is fundamentally a part of coffee, if it becomes too dominant, the entire taste experience suffers. The good news:
The cause can often be explained relatively easily.
Bitterness is partly inherent in coffee
Coffee naturally contains bitter compounds. These arise:
- in the bean itself
- during roasting
- during preparation
A certain amount of bitterness is therefore essential for a balanced espresso. Problems only arise when the coffee:
- unpleasantly sharp
- burnt
- aggressive
- or unbalanced.
Roasting plays a major role
One of the most common causes of strong bitterness is roasting.
Very dark or poorly controlled roasts can lead to:
- dominant roast aromas
- burnt notes developing
- the coffee tasting rough
High-quality roasts, on the other hand, focus on:
- balance
- harmonious intensity
- controlled bitterness
- pleasant body
Over-extraction: When too much is extracted from the coffee
Preparation also greatly influences the taste.
If coffee is extracted for too long, bitter substances are increasingly released from the coffee grounds.
Possible causes:
- too fine a grind
- too long extraction time
- too high water temperature
- too much coffee
The result:
- heavy
- dry
- bitter taste
The grind size is crucial
An incorrect grind size can change the entire flavor profile.
Too finely ground
→ Water flows too slowly
→ More bitter substances are dissolved
Too coarsely ground
→ Coffee often tastes flat or sour
The right balance is crucial for a harmonious taste.
Bean quality makes the difference
Not all coffee has the same quality.
High-quality beans often offer:
- more balanced aroma
- more pleasant bitterness
- harmonious body
- cleaner taste
Inferior green beans, on the other hand, are often roasted more heavily to mask flavor defects.
Why Italian espresso often tastes more intense
Italian espresso blends often have:
- a stronger body
- a darker roast
- more intensity
However, this does not automatically mean unpleasant bitterness.
High-quality Italian coffees focus on:
- balance
- creaminess
- harmonious roast aromas
instead of extreme harshness.
Does the coffee machine play a role?
Yes.
Factors such as:
- dirty machines
- old residues
- incorrect pressure
- poor cleaning
can also negatively affect the taste.
Regular cleaning often significantly improves coffee quality.
How can bitterness be reduced?
Many people prefer:
- balanced roasts
- high-quality beans
- correct grind size
- precise extraction
This results in a coffee that is:
- intense
- aromatic
- but not aggressive
tastes.
Conclusion
Bitterness is fundamentally part of coffee—however, balance is crucial.
Excessive bitterness often results from:
- poor roasting
- incorrect preparation
- inferior beans
- over-extraction
High-quality coffee should taste strong without being unpleasantly bitter or burnt. Because true coffee enjoyment comes from harmony, body, and balanced aromatics.