Removes caffeine with a chemical solvent, either applied to the beans directly or to the water they were soaked in.
Methylene chloride (dichloromethane) decaffeination is done directly, treating the beans with solvent in 8 to 12 rounds, or indirectly, treating the water the beans were soaked in. The earliest commercial process was patented in 1906 following Ludwig Roselius's 1903 work, and originally used benzene. The US standard requires at least 97% caffeine removal and the EU 99.9% caffeine-free by mass. Descamex, a Mexican decaf company, offers a methylene chloride European Method.
How it worksIn the direct method the beans are treated with the solvent in repeated rounds. In the indirect method the beans are soaked in water and that water is treated with solvent, then recycled with new batches.
Step by step
- 01
Direct: repeat the solvent treatment 8 to 12 times until caffeine meets the required standard.
- 02
Indirect: soak beans in water, treat the water with solvent, and recycle it through new batches.
Timing · 8-12 repeated treatments for the direct method
History
Ludwig Roselius and co-workers began the work in 1903 after Roselius observed that a consignment of coffee accidentally soaked in sea water had lost most of its caffeine while keeping its flavor, and a patent followed in 1906. The early process steamed beans with acids or bases and used benzene as the solvent.
Our notes on Methylene Chloride (Solvent) Decaffeination are still being checked against their sources, so for now this page shows only the facts we can stand behind.
What can go wrong
- Benzene was used in the earliest process and was replaced with other solvents over carcinogen concerns.
- The US standard requires at least 97% caffeine removal and the EU standard 99.9% caffeine-free by mass.
Common in
At the same stage
Sources · 2 Every sentence here was checked against a source we read. Taste notes are what guides describe, not promises about your bag. Last revised 2026-09-30.
- Decaffeination · Wikimedia Foundation
- Mountain Water Process · Descamex