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How is Coffee Decaffeinated? Top 4 Methods

How is coffee decaffeinated?

As the second most-consumed beverage in the world, coffee’s popularity can’t be denied. And we owe it all to a little chemical called caffeine.

Caffeine is a natural stimulant found not only in coffee, but tea and chocolate as well. It’s the world’s most widely consumed psychoactive drug, commonly used to jump-start the day. However, this potent little pick-me-up of a chemical has some negative side effects like jitters and the midday crash.

If you’re looking for the flavor we all love but without the crash, you may want to try the decaf option. Decaf coffee is generally coffee with 3% or less caffeine in it, and it’s rare to find a decaf coffee that is 100% caffeine-free. The coffee’s exact caffeine content depends on which decaffeinating method is used.

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The 4 Methods of Decaffeinating Coffee

There are four methods for removing caffeine from coffee beans: direct solvent, indirect solvent, supercritical carbon dioxide process, and Swiss water process.

Each of these processes requires that the coffee beans be unroasted. The coffee beans must be in their raw green state during decaffeination because the beans not only lose caffeine in this process but flavors as well. If decaf coffee were roasted first, then decaffeinated, the taste would resemble straw.

The solvent methods call for the use of either methylene chloride or ethyl acetate. These scientific names can sound a bit scary, but both solvents were deemed healthy by the US Food and Drug Administration. The FDA guidelines allow up to 10 parts per million of remaining methylene afterward. However, the decaf processes usually call for solutions containing no more than one part per million.

1. The Direct Solvent Process

To make the decaffeination process easier, the beans are softened by either soaking in water or being steamed. When ready, the coffee beans are repeatedly exposed to a solution containing either solvent, methylene chloride, or ethyl acetate.

Usually, ethyl acetate is used for this method. It’s advertised as a “natural” way to remove caffeine from coffee because the chemical is naturally found in fruits.

This process goes on for about 10 hours. Once the beans have been fully exposed to the solution, they are usually steamed to get rid of any remaining solvent.

2. The Indirect Solvent Process

The indirect solvent process begins by soaking the beans in boiling water. This draws out all the water-soluble contents, including caffeine and a lot of flavor compounds. The coffee beans are then removed from the liquid, which now contains all the water-soluble contents of the beans.

Next, methyl chloride is added to the liquid. When the liquid is heated, the methyl chloride evaporates the caffeine. Once all the caffeine is dissolved, the coffee beans are then reintroduced to the mixture to regain the flavor compounds that were lost in the initial exposure. With this, the coffee beans never contact the chemical.

This process is the most widely used method for decaffeination.

3. The Supercritical Carbon Dioxide Process

As with the above two processes, the supercritical carbon dioxide method requires water-soaked green coffee beans to start. These coffee beans are placed in a stainless steel vessel that acts like a pressure cooker.

The coffee beans are then exposed to 73 to 300 atmospheres of supercritical (highly compressed) carbon dioxide for ten to twelve hours. At this amount of pressure, carbon dioxide’s properties are enhanced, causing it to be dense like a liquid while still being a gas.

The caffeine-containing carbon dioxide that exits the container is usually filtered through activated charcoal. From there, the carbon dioxide is funneled back into the stainless steel container to repeat the process.

4. The Swiss Water Process

The Swiss water process is said to be the “cleanest” method of removing caffeine from coffee, since water is the main solvent. To start, the green beans are soaked in a mixture of water and green coffee extract.

The solution is filtered through activated charcoal, which separates the caffeine from the mixture. The solution is then channeled back into the coffee beans until they’re 99% free of caffeine.

This method began in Switzerland in the 1930s, but now the main facility operates out of Vancouver, BC. It’s also the preferred method of a lot of organic coffee companies.

RELATED READING: What are our 5 favorite decaf K-cups?

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Which Method Yields the Best Flavor?

There’s a dilemma when it comes to decaf coffee, and that is flavor. Decaf coffees just aren’t as full and vibrant as caffeinated coffees. The companies that carry out decaffeination try their best to put the flavors back into the coffee, but they’ll never be able to get back the taste of the original bean.

So, what’s the best-tasting decaf method? Really, it’s up to you. Some people love the taste of coffee that’s gone through the commonly used indirect solvent method. My personal favorite, though, is the Swiss water process. For those wanting decaf that tastes as good as regular coffee, try out decaf that’s gone through the water process.

However, it should be pointed out that roasting and brewing play a major role in taste as well. I personally recommend finding a roaster you really like. Ask about the processing of their decaf beans, and either experiment with brew methods at home or at your local coffee shop.

Featured Image Credit: Unsplash


Kate MacDonnell

Kate is a lifelong coffee enthusiast and homebrewer who enjoys writing for coffee websites and sampling every kind of coffee known to man. She’s tried unusual coffees from all over the world and owns an unhealthy amount of coffee gear.

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