When coffee is roasted, a complex process takes place inside it that releases carbon dioxide (CO₂). This phase, called coffee degassing, is fundamental for extraction quality. But what does it really mean and how long should you wait before using roasted coffee?
What coffee degassing is
During roasting, the sugars and acids in the bean transform into aromatic compounds and a large amount of CO₂ is generated. 40% of the gas is released in the first 24 hours. The rest continues to escape gradually over the following days and weeks. Degassing is therefore the natural process by which coffee beans “breathe”, releasing gases and stabilizing.
Why coffee degassing matters
If the coffee is used too early, the excess CO₂ interferes with extraction:
- it hinders the passage of water,
- it makes the crema excessively unstable and full of bubbles
- it leads to an unbalanced taste with vegetal or acidic notes.
On the contrary, if the coffee is too old and has lost almost all its CO₂, the cup will be flat and without aromatic complexity. That’s why it’s extremely important that the roast date is shown on the package. Unfortunately, in reality this rarely happens. My advice is to turn to small artisan roasteries which are instead very attentive on this point.
How long to wait after roasting
The ideal time for coffee degassing varies based on the brewing method and the degree of roast. Darker roasts generally require less time than lighter ones.
- Espresso→ wait 7-14 days after roasting for perfect balance.
- Moka→4-7 days are enough, because extraction is less intense.
- Filter (V60, Chemex, French Press)→ ideal after 10-20 days, to enhance fruity and floral aromas.
Storage and degassing
Resting is necessary after roasting. However, it’s necessary to keep in mind what the enemies of roasted coffee are.
You should avoid:
- High humidity environment
- Oxygen — Reducing the oxygen content to 0.5% in a coffee container can extend shelf life.
- Temperature — According to an SCA study, a simple 10°C increase in temperature will double the degassing rate.
To best preserve the aromas, beans should be stored in bags with a one-way valve, which allows CO₂ to escape without letting oxygen in. This keeps the coffee fresh longer and ensures consistent results in the cup. If instead you notice that the coffee package has bulged, this happens because at the time of packaging the coffee had not yet expelled the excess carbon dioxide and, in the absence of a proper valve, it can’t escape, thus inflating the package.
| Brewing method | Recommended minimum time | Ideal time | Sensory notes |
|---|---|---|---|
| Espresso | 5-7 days | 7-14 days | Stable crema, balanced aromas, full body |
| Moka | 3-4 days | 4-7 days | Sweet, round extract, less acidity |
| Filter (V60, Chemex, French Press) | 7-10 days | 10-20 days | More evident fruity and floral aromas, greater clarity in the cup |
Conclusion
Coffee degassing is an essential phase for obtaining a high-quality espresso or filter coffee. Waiting the right time after roasting means getting the most out of the roaster’s work and enjoying a cup rich in aromas, balanced, and complete.
