Extraction is the heart of coffee preparation. It describes the process in which water dissolves aromas, oils and other soluble components from the coffee grounds. The taste of your coffee - whether balanced, bitter or sour - depends directly on how much and which substances are extracted.
In this article, you'll learn how extraction works, what factors influence it, and how to navigate your way to your favorite flavor.
What does extraction mean in coffee?
Extraction is the chemical process in which hot water dissolves soluble substances from the coffee grounds. These substances are responsible for the taste, aroma and texture of your coffee.
What is extracted?
- Fruit acids: The first substances to be dissolved. They bring bright, fresh aromas.
- Sugars: Give the coffee a pleasant sweetness.
- Bitter substances: These are dissolved last and can dominate the taste if over-extracted.
The three main phases of extraction
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Early phase : Water dissolves the easily available, water-soluble substances such as fruit acids and some sugars.
Taste: Light, sour, often spicy. -
Middle phase : Sugars and oils dissolve and balance the acids.
Taste: Harmonious, sweet and complex. -
Late phase : Bitter substances and tannins are extracted.
Taste: Bitter, dry, astringent.
overextraction and underextraction
What is overextraction?
Over-extraction results in too many substances being released from the coffee grounds, particularly bitter substances and tannins.
Taste: Bitter, dry, unpleasant.
Common causes:
- Grind too fine.
- Water too hot.
- Brewing time too long.
- Too much coffee in relation to water.
Possible solutions:
- Adjust the grinding setting to a coarser setting.
- Shorten brewing time.
- Reduce water temperature to 90–96 °C.
What is underextraction?
Under-extraction means that not enough aromas were extracted from the coffee grounds.
Taste: Sour, thin, unbalanced.
Common causes:
- Grind too coarse.
- Brewing time too short.
- Too little coffee in relation to water.
- Water too cold.
- Adjust the grinding level finer.
- Extend brewing time.
- Adjust water ratio.
How do the factors grind size, brewing time and water influence the extraction?
1st grinding level
- Fine grind: Increases the surface area, allowing more extraction. Ideal for espresso.
- Coarse grind: Reduces contact time with water. Perfect for French press and cold brew.
Tip: If your coffee is too bitter, choose a coarser grind. If it tastes sour, try using finer ground coffee.
2. Brewing time
The length of time the water is in contact with the coffee grounds is crucial.
- Brewing time too long: leads to over-extraction.
- Brewing time too short: results in under-extraction.
Examples:
- Espresso: 25–30 seconds.
- Filter coffee: 3–5 minutes.
- French Press: 4 minutes.
3. Water-to-coffee ratio
An incorrect ratio will result in either a weak or overly intense coffee.
➔ Recommended: 1:15 to 1:18 (1 g coffee to 15–18 ml water). 1:2 for espresso.
Tip: Use a scale to measure precise amounts. Experiment with the ratio to find your taste.
4. Water temperature
The optimal temperature for extraction is between 90–96 °C.
- Too hot: Promotes the extraction of bitter substances.
- Too cold: Leads to under-extraction.
Tip: Use a kettle with a temperature setting to control the temperature.
How to navigate to your favorite flavor
1. Determine your preferences:
- Do you like lighter, fruitier flavors? Then experiment with a slightly shorter brewing time and a lighter grind.
- Do you prefer a fuller, sweeter flavor? Aim for a balanced extraction with a medium grind and standard brew time.
2. Test the variables:
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Change the grind size, brewing time and water temperature gradually.
-
Try different coffee-to-water ratios.
3. Conduct a tasting:
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Brew the same coffee using different settings and record the results.
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Compare the cups side by side to find the best parameters.
Practical tips for optimal extraction
- Use fresh coffee: Older beans lose their aroma.
- Stir the coffee while brewing: For even extraction (e.g. when making pour-overs).
- Keep your equipment clean: residues can negatively affect the taste.
Conclusion
The art of coffee preparation lies in the balance of extraction. By adjusting the variables - grind size, brewing time, water quality and temperature - you can perfectly match the taste of your coffee to your preferences. With patience and a willingness to experiment, you are guaranteed to find your favorite parameters for the perfect cup of coffee.
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