Decaf, plant by plant

Almost no roaster decaffeinates their own coffee. The bag says the roaster''s name, but the caffeine was removed months earlier, in a green state, by one of a small number of industrial plants — most of them in Germany, Mexico, Colombia and Canada, with a handful in Asia. Those plants are the real authors of the decaf you drink.

This is a directory of them, and of the methods they use. The short index below is the part to keep.

The quick index

Method	Solvent	Chemical?	Where it happens	What it does to the cup	Usual bag wording
Swiss Water Process	none — water + green coffee extract + carbon	No	Canada	Clean, slightly softened acidity; safest default for specialty	"Swiss Water Process", "SWP"
Mountain Water Process	none — water + extract, Mexican spring water	No	Mexico	Very similar to SWP, sometimes a touch heavier body	"Mountain Water", "MWP"
Sugarcane / ethyl acetate (EA)	ethyl acetate, fermented from cane	Technically yes, naturally derived	Colombia, at origin	Sweet, rummy, a distinct fruity-boozy note; loved or hated	"Sugarcane decaf", "EA natural"
Synthetic ethyl acetate	ethyl acetate, petrochemical	Yes	Germany, Mexico	Same chemistry, less romance	"EA process" (rarely specified)
Methylene chloride (MC, "European process")	methylene chloride	Yes	Germany, Mexico, Italy	Best flavour retention of the solvent routes; the industry workhorse	"European process", or nothing at all
Supercritical CO₂	carbon dioxide under pressure	No	Germany, Switzerland	Very neutral, gentle; industrial volumes only	"CO₂ process", "naturally decaffeinated"

Two things fall out of that table immediately.

One: silence usually means solvent. Water and sugarcane processes are marketing assets, so brands name them. Methylene chloride is not, so it goes unnamed. A bag that says only "decaf" was, on the balance of probability, decaffeinated with methylene chloride — roughly 60% of world decaffeination capacity is chemical, and MC dominates that share.

Two: "chemical" is not the same as "dangerous." Every method starts by soaking or steaming green coffee, and every method removes 97–99.9% of the caffeine. The residue argument is narrower than the internet suggests, and I take it seriously further down rather than hand-wave it.

The methods, properly

Swiss Water Process (water, no solvent)

Green coffee is soaked in green coffee extract — water already saturated with everything soluble in coffee except caffeine. Because the extract is already full of the flavour compounds, only caffeine has a concentration gradient to follow, so only caffeine leaves. The extract is then run through activated carbon sized to trap caffeine molecules, and released back into the loop. No solvent ever touches the bean; the "chemical" is water and a filter.

Cost: high. Time: slow. Flavour: reliable, slightly rounded, occasionally a little flattened in delicate washed lots. Organic-certifiable, which matters if you are building an organic line.

Mountain Water Process (water, no solvent)

Mechanically the same principle, run in Veracruz with water from the Pico de Orizaba glacier system. Descamex built it in the early 1980s. In practice MWP and SWP decafs are hard to tell apart blind; MWP is often slightly cheaper and slightly more available for small lots.

Sugarcane / ethyl acetate

Green coffee is steamed, then washed with ethyl acetate — a compound that occurs naturally in ripe fruit and is here produced by fermenting sugarcane molasses and distilling the result. The EA binds to caffeine salts, and is then washed and steamed out.

This is the only decaf method that routinely happens at origin, almost entirely in Colombia, which means the coffee is not shipped twice and more of the value stays near the farm. That is a genuine sustainability argument, not a slogan.

It is also the most opinionated method in the cup: a sweet, rum-and-raisin character that was not in the original coffee. If a decaf tastes distinctly of caramelised fruit, this is usually why.

Methylene chloride (MC / dichloromethane / "European process")

Either direct (solvent contacts the steamed beans) or indirect (solvent scrubs caffeine out of a water extract and the beans never touch it). MC is highly selective for caffeine, so it is the best of the solvent routes at leaving the rest of the coffee intact — which is why the industry keeps using it despite the reputational cost.

It boils at 40°C; roasting happens above 200°C. Residues in roasted coffee are measured in parts per billion, orders of magnitude below the US limit of 10 parts per million, and usually at or below detection. The real exposure question is occupational — the people inside the plant — not the person drinking the cup, which is why closed-loop recovery is standard in Germany and Mexico.

Where I would still avoid it: if you want organic certification (MC disqualifies it), or simply if you prefer that no petrochemical solvent be part of your food chain. That is a legitimate preference and does not need a scare study to justify it.

Supercritical CO₂

CO₂ pressurised until it behaves as both liquid and gas, pushed through moistened beans; caffeine dissolves into it, the pressure drops, the CO₂ evaporates and is recaptured. Elegant, expensive, built at industrial scale — it is what the very large brands use for very large volumes. Rare in specialty because the minimum batch sizes are enormous.

The plants

This is the genuinely hard part to compile: decaffeination is a small, private, business-to-business industry with no public register. What follows is the set of facilities that are documented — by the companies themselves, or named directly in Swiss Water''s public filings. Where a plant''s exact method mix is not published, I say so rather than guess.

North America

Swiss Water Decaffeinated Coffee Inc. — Delta, British Columbia, Canada. Swiss Water Process only. The largest chemical-free water-process decaffeinator in the world, in a purpose-built plant near Vancouver. Organic and kosher certified. Works both as a toll processor (roasters send their own green) and as a merchant. Assessment: non-chemical; the specialty default in North America.

Descamex S.A. de C.V. — Córdoba, Veracruz, Mexico. Two lines: Mountain Water Process (water) and an "EM" line using methylene chloride. Operating since 1981; the first plant of its kind in Latin America. Assessment: both — the same company will sell you either, so the process name matters more than the plant name.

Cafiver S.A. de C.V. — Coatepec, Veracruz, Mexico. Methylene chloride and ethyl acetate. Large-volume, industry-facing. Assessment: chemical (one naturally derived solvent, one not).

South America

Descafecol / Descafé — Manizales, Caldas, Colombia. Ethyl acetate, at origin, from Colombian sugarcane. The plant behind most of the "sugarcane decaf" in specialty bags worldwide, and also a producer of decaffeinated soluble coffee. Assessment: naturally derived solvent; the strongest origin-economics story of any decaf.

Brazil — soluble-linked capacity, Paraná and São Paulo state. Brazil''s decaffeination sits inside its instant-coffee industry rather than serving specialty roasters, and is not documented plant by plant. Treat any Brazilian decaf without a named process as solvent-based.

Europe

Coffein Compagnie GmbH — Bremen, Germany. The largest decaffeinator in the world, on the site where decaffeination was invented over a century ago; around 250 staff. Three routes: methylene chloride, ethyl acetate, and — since the 2020s — a water process for organic lots. Also a major producer of pure natural caffeine, which is the industry''s quiet second product. Assessment: all three categories under one roof.

CR3-Kaffeeveredelung Hermsen GmbH — Bremen, Germany. Methylene chloride plus carbon treatment, and a specialist in steaming (the Lendrich process) as a separate service. Handles both industrial and organic-certified specialty lots. Assessment: chemical, with a strong quality reputation.

Demus S.p.A. — Trieste, Italy. The Italian decaffeinator, long associated with dichloromethane alongside its own water-based line for specialty customers. Trieste''s port history makes it the southern-European counterpart to Bremen. Assessment: both, depending on the contract.

Coffein Compagnie Italy (formerly Stabilimento Testa) — Ligurian coast, Italy. Not a decaf plant: it purifies the caffeine the group extracts elsewhere. Worth knowing, because it shows where the removed caffeine goes.

Large-brand in-house CO₂ plants — Germany and Switzerland. Supercritical CO₂ decaffeination runs mostly inside the vertically integrated multinationals rather than being sold as a service, which is why you rarely see a plant name on a bag. Assessment: non-chemical, industrial scale only.

Asia

Asia is the newest and thinnest part of the map, and it is growing because the green coffee is already there.

Coffein Compagnie Vietnam — Long Thanh, Dong Nai Province, outside Ho Chi Minh City. Formerly Hiang Kie Industries, founded 2006, acquired in 2018; around 90 staff, FDA- and IFS-certified. Produces decaffeinated green coffee and natural caffeine, largely from Vietnamese robusta — which carries roughly twice the caffeine of arabica and is therefore twice as valuable as a caffeine source. Assessment: solvent-based; the route is not published lot by lot.

India — soluble-coffee decaffeination, Andhra Pradesh. Attached to India''s very large instant-coffee export industry rather than to specialty green. Solvent-based, not publicly itemised.

China, Indonesia, Japan. No significant merchant decaffeination plants serving specialty; brands there buy decaffeinated green from Germany, Mexico, Canada or Colombia.

What is actually true about safety

• Caffeine removal is 97% minimum under most regulations, and 99.9% for Swiss Water. A cup of decaf still holds roughly 2–5 mg against 80–120 mg for a normal cup. Decaf is not caffeine-free, and the genuinely sensitive will occasionally notice that residue at night.
• Methylene chloride residue limits are 10 ppm in the US; measured levels in roasted coffee are typically undetectable, because the solvent boils at 40°C and roasting reaches five times that. The pressure to ban it comes from occupational exposure and from the substance''s classification in other industries, not from measurements in brewed coffee.
• Ethyl acetate occurs naturally in fruit and in coffee itself. Whether it counts as "natural" depends entirely on whether it was fermented from cane or synthesised — and only the specialty sugarcane decafs tell you which.
• Water processes leave nothing to argue about, which is precisely their commercial value.

How to read a bag

1. A named process is a good sign — not because water is safer, but because a roaster who prints "Swiss Water" or "sugarcane EA" is a roaster who knows where their green came from.
2. No process named, cheap, supermarket shelf → almost certainly methylene chloride.
3. Organic-certified decaf cannot be MC. It is water, CO₂, or a certified EA route.
4. "Naturally decaffeinated" means nothing on its own. Ask which of the four.
5. Buy decaf fresher than regular coffee. Decaffeinated green is more porous and more fragile; it stales in weeks, not months. Most bad decaf is not badly decaffeinated — it is old.
6. Expect to pay more. Decaffeination adds a processing step, double freight in the water-process case, and roughly a tenth of the weight. A cheap decaf was made cheap somewhere.

Where we stand

Our own ranking is simple: water process first; sugarcane EA at origin a close second when we want the sweetness and want the value to stay in Colombia; CO₂ irrelevant at our scale; methylene chloride last — not because the cup is unsafe, but because the point of buying carefully is that you should never need a residue argument to feel fine about what you drink.

The more interesting fact sits underneath the whole industry: decaffeination is also caffeine production. Every tonne of decaf yields caffeine that is purified and sold on. The coffee you drink in order to sleep is funding somebody else''s late night.