How is coffee decaffeinated?
Before roasting: green beans are moistened, then caffeine is extracted using water, CO₂, or a solvent. The beans are then dried and roasted normally. About 97–99% of caffeine is removed. Swiss Water and CO₂ methods are chemical-free.
How is coffee decaffeinated?
Before roasting: green beans are moistened, then caffeine is extracted using water, CO₂, or a solvent. The beans are then dried and roasted normally. About 97–99% of caffeine is removed. Swiss Water and CO₂ methods are chemical-free.
Why that is
Decaffeination always happens to green coffee—meaning before roasting. A roasted bean would be too brittle and break apart during the process. The basic principle is the same across all methods: caffeine is extracted from the bean without destroying the other flavor compounds.
The basic process:
- Moistening the green coffee — the beans swell and their cellular structure opens up.
- Extracting the caffeine — using a solvent, water, or CO₂.
- Drying the beans — back to their original moisture content.
- Roasting normally — just like any other coffee.
The four common methods:
| Method | Solvent | Caffeine Removal | Flavor |
|---|---|---|---|
| DCM method (direct) | Dichloromethane | 97–99% | Good, very common |
| Ethyl acetate method | Ethyl acetate (from sugarcane) | 97–99% | Good, marketed as “natural” |
| Swiss Water Process | Only water | 99.9% | Very good, chemical-free |
| CO₂ process | Supercritical CO₂ | 97–99% | Very good, chemical-free |
Swiss Water Process is especially popular in the specialty scene because no chemical solvents are used. The caffeine is drawn out through osmotic pressure into “Green Coffee Extract” (caffeine-free, but flavor-saturated water)—the flavors stay in the bean.
CO₂ process uses carbon dioxide under high pressure (over 73 bar and 31 °C). In this “supercritical” state, CO₂ acts like a solvent that selectively extracts caffeine. Expensive, but very gentle.
Are solvent methods dangerous? No. Residues are far below legal limits (EU: max. 2 mg/kg dichloromethane in roasted coffee). During roasting at over 200 °C, any potential remnants evaporate completely.
In practice at Green Wall Coffee
At Sophienstraße 27, we use decaffeinated coffee treated with the Swiss Water Process—chemical-free and almost indistinguishable in taste from caffeinated coffee. For anyone wanting to enjoy coffee in the afternoon or evening without risking their sleep: our decaf is a genuine option.
Related questions
- What decaffeination methods are there?
- Does decaf coffee really have no caffeine?
- Does decaf coffee taste different than regular coffee?
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