Quick answer: Coffee is decaffeinated while the beans are still green. The beans are soaked or steamed so the caffeine can dissolve, then it is removed with a solvent (methylene chloride or ethyl acetate), with water and carbon filters (the Swiss Water process), or with pressurized carbon dioxide. The beans are then dried and roasted. Decaf still contains a little caffeine.
Decaf lets you enjoy a cup of joe without most of the caffeine. Here is how the caffeine is taken out, whether the solvents are safe, and how to choose a decaf.
In this guide 5 sections
Is decaf coffee safe to drink?
Methylene chloride is a hazardous chemical when inhaled at industrial levels, and it is considered a likely carcinogen. That is why its use in decaf is limited by regulation.
Decaf sold in the U.S. must meet FDA limits, and regulators currently consider it safe. Decaffeination was not always this safe: early decaf used benzene (see the history below).
FDA rules allow no more than 10 parts per million of methylene chloride in decaffeinated roasted coffee, which is one-thousandth of a percent. In 2023 advocacy groups petitioned the FDA to ban methylene chloride as a food solvent; as of mid-2026 the FDA had reopened comments but not yet decided. If you want to avoid it entirely, choose a decaf labeled Swiss Water, mountain water or CO2 process.
After solvent treatment, the beans are steamed and then roasted, which drives off most of the remaining solvent.
How is coffee decaffeinated? The 3 main methods
Coffee decaffeination is a complex process that happens at specialized factories separate from the coffee roasters. There are a few coffee roasters that have their own decaf processing plants, but most roasters work with separate decaffeination companies that are not in-house to decaffeinate their beans.
Generally, the process starts with water-logging the coffee beans while they are still green so the caffeine inside the bean can be dissolved by solvents and chemicals.
1. Water process (Swiss Water). Water is the only solvent. The caffeine dissolves out of the beans into water, which is passed through activated carbon filters that trap the caffeine. Swiss Water uses no chemical solvents, so its decaf can keep organic certification.
2. Solvent process. A solvent such as methylene chloride or ethyl acetate dissolves the caffeine from the beans. These solvents are applied to wet green coffee beans. Afterward, the beans are washed and steamed to remove any traces of the solvents.
3. CO2 process. The last method uses supercritical carbon dioxide to decaffeinate the beans. It is similar to the previous solvent method, but instead, it uses carbon dioxide to extract the caffeine in high-pressure containers. At high pressures, carbon dioxide becomes supercritical and becomes a solvent that is like a liquid but has the properties of a gas. When passing through the wet green coffee beans it removes the caffeine.
Personally, caffeine is one of my favorite reasons to drink coffee, and learning how decaf is made has made me pickier about which decaf I buy.
Even according to Consumer Reports, it is difficult to figure out how your coffee beans are decaffeinated. Companies are not required to say which process they use, so look for brands that name it on the bag.
Who invented decaf coffee?
The first commercial decaffeination process was developed by Ludwig Roselius, the German merchant behind Kaffee HAG.
He is said to have believed his father died from too much caffeine, and that caffeine was a “poison” in the coffee beans.
According to the popular story, the idea came by accident when a shipment of coffee beans was soaked in seawater and lost some of its caffeine.
Roselius used this as the starting point to patent a method for decaffeinating coffee beans using steam, acids, and bases. Benzene became the go-to chemical to remove caffeine for decaf coffee for a long time.
Benzene is no longer used for the decaffeination process because its carcinogenic properties.
Is decaf coffee completely caffeine-free?
No. Decaf still contains a little caffeine; the FDA says an 8-ounce cup of decaf typically has 2 to 15 milligrams. Compare that with regular coffee in our guide to how much caffeine is in coffee.
Researchers have also explored naturally caffeine-free coffee plants. It will be based on coffea charrieriana, a type of bean that lacks caffeine. In theory, this trait could be bred into other coffee plants to give caffeine-free beans.
Frequently asked questions
What is Swiss Water decaf?
Swiss Water is a brand and process that removes caffeine using only water and carbon filtration, with no chemical solvents. It is a good choice if you want to avoid methylene chloride.
Can I drink decaf coffee every day?
For most people, yes. Decaf has only a small amount of caffeine, so it is a common choice for people cutting back or drinking coffee after dinner. People who are very sensitive to caffeine should remember that decaf is not caffeine-free.
Does decaf taste different?
It can. Decaffeination can change flavor slightly, so decaf may taste a little different from the same beans with their caffeine. Swiss Water says its solvent-free process keeps the coffee close to the original.
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