The Swiss Water Process: how we decaffeinate coffee without the chemistry set

Q: How does the Swiss Water Process work?

The whole thing runs on diffusion , the same science behind a teabag steeping in hot water. Swiss Water have just refined it into something far more controlled.

9 April 2026 · 10 min read

By Alex, Founder of Raw Bean Coffee | Published April 2026

What it is, how it works, and why we won't use anything else.

Every Raw Bean decaf uses the Swiss Water Process. It's the only decaffeination method we'll touch. Water, time, temperature, and nothing else.

People ask us about this constantly. "What actually is the Swiss Water Process?" "Is it genuinely chemical-free?" "Why does your decaf taste better than the stuff I used to buy?"

Fair questions, all of them. Here's the full answer.

What is the Swiss Water Process?

The Swiss Water Process is a patented method of removing caffeine from green coffee beans using only water, temperature, and time. No chemical solvents. No artificial additives. The beans come out 99.9% caffeine-free with their original flavour intact.

The process is owned and operated by Swiss Water Decaffeinated Coffee Inc., a Canadian company based in Burnaby and Delta, British Columbia. They've been perfecting this since 1988, and their 82,000-square-foot Delta facility — which opened in 2020 and launched a second production line in 2023 — is dedicated entirely to chemical-free decaffeination.

It's the only decaffeination company in the world that focuses exclusively on a chemical-free method. That matters.

How does the Swiss Water Process work?

The whole thing runs on diffusion, the same science behind a teabag steeping in hot water. Swiss Water have just refined it into something far more controlled.

Creating the flavour water

A batch of green coffee beans goes into pure, clean water. This creates what Swiss Water call Green Coffee Extract (GCE for short), a solution loaded with all the water-soluble compounds found naturally in coffee. The flavour compounds, the oils, the good stuff.

This initial batch of beans is then composted. Their job was to create the GCE, and that only needs to happen once.

The caffeine trap

The GCE passes through activated carbon filters designed to trap caffeine molecules and only caffeine. The flavour compounds pass straight through because they're a different molecular size. After this step, the GCE is caffeine-free but still saturated with all those flavour compounds.

The swap

This is where it gets interesting. Fresh green coffee beans go into this caffeine-free, flavour-saturated GCE. Through natural diffusion, caffeine migrates out of the beans and into the extract. But because the GCE is already fully saturated with the flavour compounds, those flavours have nowhere to go. They stay in the bean.

The caffeine moves out. The flavour stays put.

Drying and quality control

The beans are dried under low-temperature, high-airflow conditions to match their original moisture profile. Every batch is sampled and cupped — pre- and post-decaffeination — to make sure the flavour profile has been preserved.

The process repeats until the beans hit 99.9% caffeine-free. The whole thing takes around 8 to 10 hours per batch.

Why we chose the Swiss Water Process (and nothing else)

There are four main ways to decaffeinate coffee. We tried the alternatives and kept coming back to Swiss Water. Here's the comparison.

The other three methods

Methylene Chloride Process — The cheapest and most widely used method. It rinses beans in methylene chloride, a chemical solvent. Effective at removing caffeine, but methylene chloride is classified as a Group 2A "probable carcinogen" by the International Agency for Research on Cancer (IARC). The U.S. EPA identifies it as a known carcinogen linked to liver cancer, lung cancer, and neurotoxicity. Residues are strictly regulated, but they're still present in trace amounts. This is what most budget supermarket decafs use.

In April 2024, the EPA finalised a ban on most industrial and consumer uses of methylene chloride, effective July 2024. Separately, the Environmental Defense Fund petitioned the FDA in December 2023 to remove methylene chloride from the list of permitted food additives — citing the Delaney Clause, which prohibits FDA-approved food additives that cause cancer. That petition remains under FDA review. The fact that a chemical banned for paint stripping is still permitted in coffee decaffeination tells you something about how slowly food regulation moves.

Ethyl Acetate (Sugar Cane) Process — Uses ethyl acetate, a compound found naturally in fruits, as a solvent. Sometimes marketed as "natural decaf" because of this. The catch: ethyl acetate isn't flavour-neutral. Of all the methods, it has the biggest impact on the original taste of the beans. You can often tell the difference.

Supercritical CO₂ Process — Uses pressurised carbon dioxide to extract caffeine. It's efficient, leaves no chemical residues, and preserves flavour well. The downside is the high energy demands. It's the closest competitor to Swiss Water in quality terms.

Why we chose Swiss Water

Swiss Water adds zero chemical solvent residues. Zero. It keeps the origin flavours, taste, and aroma of the coffee better than any other method. And it's environmentally sound: more than 80% of the water used is returned clean to local waterways, and the carbon filters are renewable.

We spend serious time sourcing great single-origin beans. Why would we then let a decaffeination process strip out what makes them special?

Our Swiss Water decaf range has won six Great Taste Awards, including a 2-star in 2025 for our Definitely Decaf Perfect Pods. We're the #1 selling Swiss Water Process decaf brand in major UK supermarkets. The process works.

Is Swiss Water Process decaf really chemical-free?

Yes. Completely.

The Swiss Water Process uses water, temperature, time, and activated carbon. That's the full ingredient list. No methylene chloride. No ethyl acetate. No chemical solvents of any kind.

The process holds certifications including Organic (OCIA/USDA), Kosher, Halal, Fairtrade, Rainforest Alliance, UTZ, and 4C — with organic certification maintained by the Organic Crop Improvement Association in accordance with USDA National Organic Program standards, and Kosher certification from the Orthodox Rabbinical Council of British Columbia.

When we say "chemical-free," we mean it. There's nothing in our decaf that wasn't already in the coffee bean or the water.

Does Swiss Water decaf taste different?

Good Swiss Water decaf should taste like the coffee it was before decaffeination. That's the point of doing it this way.

Caffeine itself is bitter, so removing it can make the cup slightly smoother. Some people notice a bit less brightness or a gentler acidity. But with Swiss Water, the complex flavour compounds — the fruity notes, the chocolate undertones, the body — all stay where they belong: in the bean.

Swiss Water samples every batch before and after decaffeination. They cup both versions side by side to make sure the flavour profile has been maintained. If a batch doesn't pass, it doesn't ship.

At Raw Bean, we roast our Swiss Water decaf with the same care as our regular coffee. The gas-flushing we use during packaging removes oxygen to keep everything fresh. The result? Decaf that most people genuinely can't distinguish from the regular version.

"I didn't know decaf could taste this good" is probably the most common email we get.

How much caffeine is left?

Swiss Water Process coffee is 99.9% caffeine-free. In a typical 240ml cup of brewed decaf, that translates to roughly 2–15mg of caffeine, compared to around 95mg in a regular cup.

To put that in perspective — a bar of dark chocolate has more caffeine than a cup of our decaf.

In the UK, regulations require decaffeinated coffee to contain no more than 0.1% caffeine by dry weight for roasted and ground coffee, and 0.3% for soluble/instant coffee extracts. The EU standard under Directive 1999/4/EC sets the same limits. Swiss Water meets and exceeds this standard.

For most people, the trace amount left in decaf is completely unnoticeable. You won't get the jitters. You won't lie awake at night. It's as close to caffeine-free as real coffee gets. We've covered more on this in our guide to how much caffeine is in a decaf coffee.

Is Swiss Water decaf safe during pregnancy?

Most healthcare professionals agree that decaf is safe during pregnancy. The NHS recommends limiting caffeine to 200mg per day during pregnancy. A cup of Swiss Water decaf has roughly 2–5mg — well within that limit.

Because the Swiss Water Process uses zero chemical solvents, there's no concern about chemical residues either. For expecting mums who miss their daily coffee, Swiss Water decaf is the safest, cleanest option available.

As always, talk to your midwife or GP if you have specific concerns — but for most, decaf is a smart swap during pregnancy. You might also want to read our post on the health benefits of decaf coffee.

The environmental side

The Swiss Water Process was built as a direct alternative to chemical decaffeination. That environmental thinking carries through the whole operation.

More than 80% of water used is returned clean to local waterways. The remaining water is absorbed during coffee hydration. There are no solvents to dispose of and no chemical runoff. The activated carbon filters are renewable and reusable. And the process maintains Organic, Fairtrade, Rainforest Alliance, UTZ, and 4C certifications.

The UK decaffeinated products market is forecast to reach $275 million (approximately £216 million) by 2032, growing at 7.72% annually. As more people switch to decaf, how that coffee gets decaffeinated matters.

Swiss Water Process vs other methods: a quick comparison

	Swiss Water	CO₂	Ethyl Acetate	Methylene Chloride
Chemical-free	Yes	Yes	No (solvent)	No (solvent)
Flavour preservation	Excellent	Good	Moderate	Moderate
Organic compatible	Yes	Yes	Varies	No
Cost	Premium	Premium	Mid-range	Low
Environmental impact	Low	High energy	Moderate	Higher
Caffeine removal	99.9%	99.9%	97–99.9%	97–99.9%
Used by Raw Bean	Yes	No	No	No

Getting the best from your Swiss Water decaf

The beans and the process do the heavy lifting. But storage and brewing make a difference too.

Keep your decaf in an airtight container, away from light, heat, and moisture. Don't put it in the fridge — coffee absorbs odours and moisture. A cool, dark cupboard is perfect. Decaf can stale slightly faster than regular coffee because the decaffeination process makes the beans a touch more porous, so buy in quantities you'll use within a few weeks.

If you can, grind fresh. Whole beans stay fresh longer than pre-ground. Grind right before brewing and you'll notice the difference.

Swiss Water decaf works with any brew method — espresso, pour-over, cafetiere, AeroPress, cold brew. For cold brew, the naturally lower acidity combined with Swiss Water's gentle decaffeination makes for a really smooth, sweet cup. Perfect for summer.

All our Raw Bean decaf is gas-flushed during packaging to remove oxygen and lock in freshness. So even if you prefer the convenience of pre-ground, you're starting from the best possible base.

Why we're a Swiss Water partner

We chose Swiss Water because they think about coffee the same way we do. Honest ingredients. No hidden chemicals. Flavour first.

We've been sourcing and roasting Swiss Water decaf for years now. It's how we ended up as the #1 Swiss Water Process decaf brand in major UK supermarkets, and why our Definitely Decaf range has picked up six Great Taste Awards — including a 2-star for our Perfect Pods in 2025.

If you reckon decaf can't compete with "real" coffee, give ours a go. We think you'll be surprised. Got more questions? Check our decaf FAQ — we've answered the lot.

Shop our Swiss Water Decaf range →

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