What decaffeination methods are there?
Four common methods: 1) DCM method (dichloromethane), 2) Ethyl acetate method, 3) Swiss Water Process (only water, chemical-free), 4) CO₂ process (supercritical carbon dioxide). Swiss Water and CO₂ are considered the best tasting and work without organic solvents.
Why that is
All methods share the same goal: extract caffeine from the green coffee bean without destroying its flavor compounds. This is harder than it sounds—caffeine only makes up 1–2.5% of the bean, and there are hundreds of other compounds that need to be preserved.
1. DCM method (Direct solvent method)
- How: Green coffee is steamed, then rinsed with dichloromethane (DCM), which selectively dissolves caffeine. The solvent is then removed, and the beans are dried.
- Pro: Efficient, cost-effective, preserves flavors well.
- Con: Chemical solvent—residues are subject to an EU limit (2 mg/kg), and most evaporate during roasting at 200+ °C.
- Prevalence: The most common method worldwide, especially in Europe.
2. Ethyl acetate method (EA)
- How: Similar to DCM, but using ethyl acetate as the solvent. Often marketed as "naturally decaffeinated" because ethyl acetate also naturally occurs in fruit.
- Pro: "Natural" image, good flavor.
- Con: The ethyl acetate used industrially is usually synthetic. Can leave slightly fermented notes.
- Prevalence: Common for coffees from Colombia and Brazil.
3. Swiss Water Process (SWP)
- How: Green coffee is soaked in water that is already saturated with flavor compounds (but contains no caffeine). Through osmotic pressure, only the caffeine dissolves into the water. No solvent required.
- Pro: 100% chemical-free, 99.9% caffeine removal, great taste.
- Con: More expensive, can slightly mute some flavor notes.
- Prevalence: Popular in the specialty scene, especially in North America.
4. CO₂ process (Supercritical)
- How: CO₂ is pressurized to over 73 bar and heated to 31 °C—in this "supercritical" state, it acts like a solvent and selectively extracts caffeine.
- Pro: Highly selective, chemical-free, excellent flavor.
- Con: Very expensive due to the high-pressure equipment.
- Prevalence: Industrial scale for large volumes, increasingly used for specialty coffee as well.
Taste ranking (subjective, but an industry standard): CO₂ ≈ Swiss Water > DCM > Ethyl Acetate.
In practice at Green Wall Coffee
At Sophienstraße 27, our decaf is decaffeinated with the CO₂ process. When sourcing, we pay close attention to the decaffeination method because it noticeably impacts the taste.
Stop by Sophienstraße 27 in Berlin-Lichtenberg — Mon–Fri 8am–5pm, Sat 10am–5pm.
Further reading
Related questions:
- Does decaf coffee really have no caffeine?
- Does decaf coffee taste different than regular coffee?
- How is coffee decaffeinated?
Also relevant:
- What does Third Wave Water mean? — Water & Water Quality
- What is the difference between the classic and inverted method? — AeroPress
All questions in this topic: Decaffeinated Coffee