Why does coffee taste bitter?

Vietnamese Coffee Exporter
Why does coffee taste bitter?

Why does coffee taste bitter? – I don’t know when, but when we talk about coffee, we will imagine a dark brown drink with a bitter taste. Try to find out why, even though there is a balance between the sour, sweet, and bitter flavors… but the bitterness of coffee is still dominant. Where does the bitter taste in coffee come from? 

Chemical basis of coffee bitterness

The human tongue has a unique structure with many regions. Each language area will take on the responsibility of perceiving different flavors such as sour, salty, sweet, bitter (particularly for spicy, it is felt through it. brain). The only bitter taste is felt in all tongue areas because the receptor cells on the tongue’s surface react when we taste anything painful.

Usually, we think that the bitterness in coffee is primarily dependent on the caffeine content, but in fact, this is not the case; bile is made up of many other compounds. Commonly known compound names are: Phenol, Flavonoid, Catechin,

The second finding of bitterness in coffee is that it’s not just Caffeine that irritates. Still, many other compounds, and most of them don’t even have a similar chemical structure. Some familiar names include phenols (and polyphenols), flavonoids, catechins, types of Chlorogenic Acid, and Caffeine. Caffeine plays a role in creating the great bitterness of coffee and the addictive agent of coffee.

Why does coffee taste bitter?
Why does coffee taste bitter?

Chlorogenic Acid

The second agent behind Caffeine is Chlorogenic Acid, which also causes bitterness in coffee.

  • There are 82 types of Chlorogenic Acid in green coffee beans. The primary Acid responsible for the bitter taste is 3-CGA, followed by mono, di, and Feruloyl Quinic.
  •  The chlorogenic acid content in Arabica beans is 6-7% and in Robusta beans is 10%, which explains why Robusta’s extract has a more bitter taste than Arabica.
  • Chlorogenic Acid is a natural antioxidant. Recent research indicates that coffee beans contain higher antioxidants than green tea.

90% of the total Chlorogenic Acid content (7% solids in green coffee) is entirely reactive. When the Chlorogenic Acids break down, this reaction forms coffee and caffeine’s bitter taste. In the combination of products created from the decomposition of Chlorogenic Acid, there will be a typical compound, Caffeic Acid – an essential intermediate creating a bitter taste that makes us think of the characteristic bitter taste of Espresso.

Sensory science of bitter taste in coffee

Sweet – Bitter is usually two contrasting and clearly defined flavors when making comments about the taste of something. The truth is not so; in some cases, they react and complement each other to increase and decrease the perception of coffee, especially coffee.

You can try the following: if you drink water, then bite and suck all the juice from the inside of that slice of lemon and then drink the water again, don’t be surprised if the water you drink tastes as sweet as sugar again.

In the world of sensory evaluation, this phenomenon is called Reference Point. If you perceive a taste at a neutral level that is the most accurate, if you perceive the like to be enhanced, it will be beyond the threshold of perception, and your perception of other flavors will increase. If you eat soft sweet cakes and try the coffee right after, you will feel much more bitter than before.

Why does coffee taste bitter?
Why does coffee taste bitter?

In addition, environmental factors also significantly affect the perception of the taste of coffee. Unexpected factors affect the taste, like drinking a cup of coffee on the beach (the salt concentration in the air is high), on the top of a mountain (when the air is thinner), in a coffee shop.

Factors affecting bitterness in coffee

The bitterness in coffee also depends on how the coffee is drunk. For comparison, traditional Vietnamese black coffee served at friendly sidewalk cafes will be more bitter than foreign coffee. Even coffee extracted by the Espresso method is not as painful as black ice. of Vietnam, besides the bitter taste, you will not feel anything else.

Origin – species

The variety of coffee beans is the primary factor determining the bitterness of coffee beans due to the content of chemical components available in the types of green coffee beans. As mentioned above, the full range of Chlorogenic Acid in Robusta is 10%, and Arabica is only 6-7%, not to say that the caffeine content is near twice as large as Arabica, so the Robusta coffee bean will be more bitter.

bitter taste of coffee


The conditions of the geographical environment and the farming method of the farmer, if all goes well and the seeds are harvested at a mature stage, the content of substances will be at its peak, and the taste of the beans will also be different.

bitter taste of coffee

Roasting process

The original green coffee bean will not have bitterness or any flavor associated with the coffee’s extraction. The new roasting process is a giant chain reaction to create the coffee flavor we feel every day. Chlorogenic Acid compounds will be metabolized gradually based on temperature and time of heat exposure.

In conclusion, when roasted from Light, Medium, and Dark Roast levels, coffee will have increasing bitterness and decreasing acidity because the darker the roast, the more Chlorogenic Acid will be converted.

Why does coffee taste bitter?
Why does coffee taste bitter?

How to make coffee less bitter?

Want a less bitter cup of coffee? Through the knowledge outlined above, the simplest way is to choose high-quality Arabica beans that are lightly roasted when you make a cup of coffee. In addition, in the process of coffee extraction, Barista has enough knowledge in hand to be able to control the bitterness: water temperature, hot water contact time during the extraction, grain grind size.

  • Each brewing method requires a different fineness of ground coffee beans. When grinding too finely, the total surface area of ​​the coffee mass increases, and more flavors are extracted, which can increase bitterness.
  • The hotter the water temperature, the more coffee will be extracted. The temperature of the water used for preparation is too high, leading to a bitter taste.
  • The longer the extraction time, the more the flavors will degrade and become negative; the result of too long extraction is an extract with only a bitter taste.

>>>Why does coffee taste bitter?



Helena Coffee Vietnam

Helena Coffee Processing & Export in Vietnam | Helena., JSC, which was established in 2016, is a Vietnamese coffee exporter, manufacturer & supplier. We provide the most prevalent varieties of coffee grown in Vietnam’s renowned producing regions.

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