Who knew that a simple cup of coffee contained so many scientific secrets? From bean to cup, discover the chemical reactions that make coffee a drink as complex as it is addictive.

1. The chemical components of coffee

Each cup of coffee contains more than 1,000 chemical compounds, each contributing to its unique aromas and flavors:

  • Caffeine : A natural stimulant that boosts focus and energy.
  • Chlorogenic acids : These antioxidants present in green beans are transformed during roasting, influencing the acidity of the coffee.
  • Sugars : Caramelized under the effect of heat, they bring sweetness and aromatic complexity.
  • Volatile oils : They release varied aromas, ranging from floral notes to chocolatey or spicy nuances.

2. Roasting: a festival of chemical reactions

Roasting is the key step that transforms green beans into real aromatic treasures. Two main reactions come into play:

Maillard reaction

  • Interaction between sugars and proteins, creating toasted, nutty, and caramel aromas.

Caramelization

  • Sugars degrade around 150°C, producing sweet and slightly bitter flavors.

Impact of roasting degree

  • Light roasting : Fruity and acidic notes.
  • Dark Roast : Chocolatey, smoky, and full-bodied flavors.

3. Extraction: a question of chemistry and precision

Extraction is the art of balancing water and coffee compounds. Here are the key factors:

  • Ideal temperature : Between 90°C and 96°C. Water that is too hot burns the aromas, while water that is too cold under-extracts the coffee.
  • Extraction time : Varies depending on method (30 seconds for espresso, 4 minutes for French press).

The extracted compounds

  • Acids : First released, giving liveliness and fruity notes.
  • Sugars : Bring balance and sweetness.
  • Bitterness : Comes last, especially in cases of over-extraction.

4. Grinding and milling: the science of detail

The grind size directly influences the extraction:

  • Grinding too fine : Fast extraction → Bitter coffee.
  • Grinding too coarse : Under-extraction → Acidic and weak coffee.
    Choose a grind that suits your method (espresso, filter, plunger).

5. Flavors and aromas: a chemical symphony

Each coffee contains more than 800 aromatic compounds, influenced by:

  • Origin : An Ethiopian coffee is often floral and fruity, while a Brazilian coffee will be rounder and chocolatey.
  • The preparation method : A filter coffee maker offers a delicate taste, while an espresso is more intense and concentrated.

To conclude

Coffee is a science of taste, where every step – from cultivation to cup – plays a key role. Next time you enjoy a cup, think about the incredible chemistry behind every sip.

Enjoy your meal! ☕

Back to blog