The Swiss Water Process removes 99.9% of the caffeine from green coffee beans using nothing more than water, temperature, time and activated carbon filters. No solvents touch the beans at any stage. A regular cup of coffee contains around 95 to 100mg of caffeine. A Swiss Water decaf typically contains between 3 and 15mg depending on serving size and brew method.
The method matters when you are picking decaf because it shapes the cup. Some methods strip flavour with the caffeine. Some leave behind solvent residue that careful drinkers would rather avoid. Swiss Water sits firmly in the specialty bracket. Solvent free, third-party certified, and used by 25 UK and Ireland roasters in the Decaffeinate directory.
This is how the process works, what to expect in the cup, and how it stacks up against the alternatives.
How the Swiss Water Process works
The full cycle runs 8 to 10 hours per batch and breaks into four stages. The mechanism is simple in principle, slightly counterintuitive in practice.
1. Hydration
Green, unroasted beans are cleaned of silver skin and debris, then pre-soaked in clean water. The soak expands the bean structure so caffeine can migrate out efficiently in the next stage. Nothing is removed yet. The beans are being primed.
2. Caffeine migration into Green Coffee Extract
The hydrated beans are immersed in Green Coffee Extract, a proprietary water solution that already contains every soluble flavour compound found in green coffee, but no caffeine. Because the GCE is caffeine-lean and the beans are caffeine-rich, caffeine diffuses out of the beans into the solution down the concentration gradient.
The flavour compounds stay put. The solution is already saturated with them, so there is no gradient to drive them out of the bean. This is what stops a plain water bath from stripping the cup along with the caffeine.
3. Carbon filtration
The caffeine-saturated GCE is passed through activated carbon filters. Caffeine molecules bind to the carbon. Smaller flavour molecules pass through. The cleaned GCE goes back into circulation for the next batch. Closed loop. Spent carbon is sent to a furnace, the caffeine is burned off, and the carbon is reused. Around 85% of the process water is returned to community supply.
4. Drying
Decaffeinated beans are dried back down to standard green coffee shipping moisture, roughly 11%, using high airflow and low temperatures. They are then bagged and shipped to roasters around the world.
The process was developed in Switzerland in 1933, taken commercial by Coffex S.A. in 1980, and licensed under the Swiss Water brand from a Burnaby, British Columbia plant in 1988. Today’s facility sits in Delta, BC. All certified Swiss Water decaf in the world passes through it.
What does Swiss Water decaf taste like
Good decaf tastes like good coffee. Bad decaf tastes like bad coffee. The decaffeination method shapes the edges of the profile, not its substance.
In a well-roasted Swiss Water decaf, expect a clean cup with chocolate, caramel and nut tones, and some loss of the most volatile aromatic compounds that give caffeinated coffee its top notes. The bias of the method is towards comfort flavours. Look at the tasting notes on the 25 Swiss Water coffees in the directory and the pattern repeats. Almond, cocoa, milk chocolate, hazelnut, toffee. The chocolate gravity is real.
That bias relaxes on the right origins. Apostle Coffee’s Sumatran lands at butterscotch, marjoram and nutmeg. The Studio Coffee Roasters’ Bolivian adds sultana and clementine alongside the milk chocolate. Caribe Coffee’s Honduran Strictly High Grown sits at walnut and toffee. The process does not flatten origin character. Cheap green beans and lazy roasting do that.
Swiss Water versus the other decaf methods
Four commercial decaffeination methods are in use today. Two are specialty grade. Two are not.
| Method | Mechanism | Solvent free | Flavour signature | Cost |
|---|---|---|---|---|
| Swiss Water | Water and GCE, caffeine stripped via activated carbon | Yes | Clean, chocolate-leaning, slight loss of top aromatics | High |
| Supercritical CO2 | Pressurised liquid CO2 binds caffeine selectively | Yes | Strong retention of body and lipids. Suits espresso | Highest |
| Ethyl Acetate (sugar cane) | Naturally derived EA binds caffeine, beans washed and dried | No (natural solvent) | Slight sweetness boost. Often processed at origin | Moderate |
| Methylene Chloride | MC solvent binds caffeine, evaporates in roasting | No (synthetic solvent) | Industry chemists rate this best at flavour retention. Reputational risk dominates | Lowest |
Swiss Water and CO2 are the two specialty grade options. Sugar cane ethyl acetate done well at origin in Colombia is increasingly excellent and keeps value with the producing country. Methylene chloride is the cheapest method and the one specialty roasters refuse to use, both because the residue is a probable carcinogen and because the reputational ground has already been ceded to the alternatives.
Is Swiss Water decaf really chemical free
The marketing line is “100% chemical free”. The accurate version is “no organic solvents used”.
Water is a chemical. Activated carbon is a chemical structure. Every food process on earth involves chemicals, so the slogan is technically loose. A careful explainer should reach for the more accurate framing.
The substance of the claim holds. Methylene chloride and ethyl acetate are both organic solvents applied to the beans. Swiss Water uses none. The process is certified organic by the Organic Crop Improvement Association (OCIA), which is independent third-party verification rather than a brand assertion. If solvent residue is the reason you are buying decaf, Swiss Water genuinely delivers it. The chemistry is honest. Only the slogan is sloppy.
Which UK roasters use Swiss Water
The Decaffeinate directory currently lists 25 Swiss Water coffees from 25 UK and Ireland roasters. Nineteen are active (11 live, 8 out of stock at time of writing) and 6 are inactive as roasters rotated their decaf SKU.
Origins skew South American. Eighteen of the 25 come from Peru, Colombia or Brazil (six each). The rest cover Guatemala, Honduras, Indonesia, Bolivia and one multi-origin blend. Active price band runs £7.25 to £24.94 per 250g, with a mean around £11.69 and the bulk clustered between £9 and £12.
A representative spread across origin, price and roaster:
- Apostle Coffee, The Needle’s Eye Organic Decaf (Indonesia, £15.55). The only Sumatran Swiss Water in the directory. Permata Gayo cooperative origin. Butterscotch, marjoram, nutmeg.
- Artisan Roast, Decaf Brazil Swiss Water (Brazil, £9.50). The archetypal Brazilian at a sensible price. Almond, molasses, cocoa.
- The Studio Coffee Roasters, Bolivia Sparkling Water Decaf (Bolivia, £12.44). The only Bolivian on the list. Caramel, sultana, clementine, milk chocolate.
- Caribe Coffee, Swiss Water Decaf SHG (Honduras, £15.63). A Honduran Strictly High Grown. Walnut and toffee.
- Bad Hand Coffee, Decaf (Colombia, £14.00). Bournemouth roastery, well-regarded in UK specialty circles. Chocolate, apple, toffee.
- York Coffee Emporium, The Dame House Decaf (Brazil, £24.94). Top of the price band. Hazelnut, milk chocolate, caramel.
- Insurgence Coffee, Retreat Decaf (Brazil, £7.50). Bottom of the price band. Dark chocolate, nut.
That covers seven. There are eighteen more. Browse the full directory and filter by Decaf Method = Swiss Water to see them all.
Swiss Water versus CO2: which is better
It depends on how you brew.
For espresso, CO2 has the edge. Supercritical CO2 binds selectively to caffeine and leaves more of the lipids intact, which translates to better crema and a fuller mouthfeel under pressure. The category is rarer and pricier in the UK, but worth seeking out if espresso is the daily driver.
For filter and pour over, Swiss Water is the practical default. Widely available across UK specialty, reliably good, and removing marginally more caffeine (99.9% vs 97 to 99% for CO2). Clean, chocolate-leaning, easy to roast well.
Neither method is wrong. Most drinkers will not reliably tell the two apart in a blind cupping of equivalent origins. The variables that matter more are the quality of the green bean, the freshness of the roast, and the discipline of the person making the brew that morning.
Where to start
If you want to try Swiss Water rather than just read about it, the directory has 25 coffees from UK and Ireland roasters across Peru, Colombia, Brazil and a handful of more interesting origins. Start with Artisan Roast’s Brazilian for a representative entry point at £9.50, or Apostle Coffee’s Sumatran for something that breaks the chocolate pattern.
Browse the full directory and filter by Decaf Method = Swiss Water for all 25.