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The difference between Swiss Water decaf and “regular” decaf is how the caffeine is taken out. Swiss Water uses only water, green coffee extract and carbon filters. Most other decaf, especially in supermarkets, is made with a solvent: methylene chloride or ethyl acetate. A third option, carbon dioxide, is also solvent free. All of them leave very little caffeine; they differ in flavour, cost and whether an organic coffee can stay organic.
| Method | What removes the caffeine | Does a solvent touch the beans? | Flavour impact | Relative cost | Organic coffee can keep certification? |
|---|---|---|---|---|---|
| Swiss Water | Water and caffeine-free green coffee extract; caffeine caught on carbon | No solvent used | Low; designed to leave other compounds in the bean. Some tasters find it slightly softens flavour | Higher | Yes, the process is certified organic |
| Carbon dioxide (CO2) | Pressurised CO2, caffeine caught on carbon | No solvent used | Low; CO2 is very selective for caffeine | Higher; expensive equipment | Yes, commonly used for organic decaf |
| Ethyl acetate (“sugar cane”) | Ethyl acetate, often from fermented sugar cane | Yes, directly | Moderate; often described as sweet and slightly fruity | Medium | Not usually |
| Methylene chloride, direct | Dichloromethane rinsed through steamed beans | Yes, directly | Low to moderate; quite selective | Lowest | No |
| Methylene chloride, indirect | Beans soaked in water; the water is treated with dichloromethane, then returned to the beans | Not directly; it treats the soaking water | Low to moderate | Low | No |
Flavour ratings are generalisations. The green coffee and the roast usually matter more than the method.
There’s no official term, but people usually mean decaf made with a chemical solvent, and in practice that’s often methylene chloride. The coffee specialists Kaffeemacher describe the methylene chloride process as the most common and cheapest. CO2 is also widely used for large-volume supermarket decaf, so a pack that just says “decaffeinated” could have been made by any of these methods.
Green beans are soaked in a caffeine-free extract of green coffee for 8 to 10 hours. Caffeine moves out into the extract, which is already saturated with the coffee’s other soluble compounds, so those largely stay in the bean. Carbon filters trap the caffeine and the extract is reused. The full step by step is in our guide to what Swiss Water decaf is.
Invented by Kurt Zosel at the Max Planck Institute for Coal Research and patented in 1970, this method moistens the beans, then passes CO2 through them at high pressure. In the classic version described by the Max Planck Society, that’s 70°C and 162 bar, where CO2 behaves partly like a liquid and partly like a gas. The caffeine is then caught on activated carbon. CO2 leaves no residue, but the plant is expensive to build and run, so it suits large volumes.
Ethyl acetate occurs naturally in fruit and is also made by fermenting sugar. The best-known sugar cane decaf comes from Descafecol in Colombia, where green coffee is steamed, moistened and then washed repeatedly with ethyl acetate made from local sugar cane, until at least 97% of the caffeine is gone. Steam then strips out remaining solvent. These decafs are often sold as “natural decaf” or “naturally decaffeinated”, which is accurate in that the solvent can come from a natural source, but it’s still a solvent.
In the direct method, steamed beans are rinsed with methylene chloride (also called dichloromethane), which bonds with the caffeine. The beans are then steamed again to drive off the solvent. In the indirect method, sometimes called the European method, the beans soak in hot water; that water is drawn off, treated with the solvent to remove the caffeine, heated to evaporate the solvent and returned to the beans so they reabsorb their flavour compounds.
It works well, and it’s cheap. The concern is the solvent itself. Methylene chloride is hazardous at industrial exposures, and in 2024 the US Environmental Protection Agency banned most of its non-food uses. Regulators still consider trace residues in coffee safe: the UK and EU cap them at 2 mg per kg of roasted coffee, and the US allows up to 10 parts per million. A petition asking the FDA to remove it from food was still undecided in mid-2026. We would put it this way: the residue limits are strict, but if you’d rather avoid it altogether, you can.
Every method has to soak the beans, and anything that dissolves caffeine will pull out some flavour too. The question is how selective it is. Kaffeemacher’s summary is that methylene chloride is more selective than its reputation suggests, ethyl acetate a little less so, and slow subcritical CO2 the most selective of all. Swiss Water takes a different route, using a saturated extract so the other compounds have nowhere to go.
In the cup, a good green coffee decaffeinated by any of these methods and roasted carefully will beat a poor coffee done by the “best” method. Ethyl acetate decafs are often described as sweet with a slightly fruity edge. Swiss Water decafs tend to taste clean and true to origin, though some professionals feel the process blurs flavour slightly. We chose Swiss Water because we liked the result with our Brazil, and because it means no solvent at all.
Not much. Swiss Water removes 99.9% of the caffeine. In the US, decaf must have at least 97% removed, while in Germany and Switzerland roasted decaf must contain no more than 0.1% caffeine by dry weight; there’s no harmonised EU limit for beans, only for instant at 0.3%. Whatever the method, a cup of decaf usually contains just a few milligrams. If caffeine itself is your concern, the method matters less than the fact it’s decaf. Our article on the benefits of Swiss Water decaf covers what that means for sleep and pregnancy.
If a roaster can’t tell you how their decaf was made, that tells you something too.
There’s no evidence that it changes health outcomes, because regulated solvent residues are tiny. Its advantage is that there’s no solvent residue at all, which some people prefer.
It’s only carried out at Swiss Water’s own plants in Canada, and the extracted caffeine isn’t sold on, so there’s no by-product income to offset the cost.
It avoids solvents entirely, which is a real advantage, but there are trade-offs around water, energy and shipping. We look at them in how environmentally friendly Swiss Water decaf is.
Both are solvent free and both suit organic coffee. CO2 is very selective, so a well-made CO2 decaf can be excellent. It’s usually run at large scale, which is why it turns up so often in big-brand decaf.
Our own Swiss Water Decaf is a natural-process Brazil from the Cerrado with roasted peanut and milk chocolate notes. If you’ve only ever had supermarket decaf, it’s a good way to find out what the method can do. Browse the rest of our decaf collection for anything else without the caffeine.
