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Differences between coffee decaffeination methods

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  • Melissa Collins Author: Melissa Collins
  • Updated: July 2, 2021

Coffee decaffeination methods

One in ten coffee-lovers drinks decaf, studies say. For various reasons, these people enjoy the taste of coffee, but do not want to have to deal with the stimulating effects of caffeine.

So if you’re shopping for decaf coffee, here’s a quick guide that explains the different methods of how a regular coffee bean becomes a special decaf bean. Let’s dive right in.

Difference between regular coffee and decaf

The process of removing caffeine from coffee beans is called decaffeination and it is very tricky because it is quite hard to remove just the caffeine, leaving all the natural flavors in place. However, this does not mean that decaf is 100% caffeine-free.

Regular coffee contains around 70 mg of caffeine per cup, while decaf only contains 7 mg per cup.

How do roasters decaffeinate coffee?

Basically, there are four decaffeination methods in use today. What they all have in common is that they are applied to green coffee beans, before they are roasted.

Since caffeine is water-soluble, all decaffeination methods involve water. However, there are two solvent-based methods, which use chemicals to eliminate caffeine, and two non-solvent based ones.

Solvent-based decaffeination methods

  • The direct solvent-based decaffeination method is the harshest and raises a lot of questions. Green coffee beans are first steamed to open up the pores, then rinsed with either methylene chloride, or ethyl acetate, which act as decaffeination agents.

    The washing process takes about ten hours, until caffeine molecules are vastly eliminated. Nobody likes the idea of drinking coffee that’s been soaked in chemicals for hours, but you must know both compounds are FDA approved.

  • The indirect solvent based decaffeination method means that the chemical solvents never touch the beans themselves. The process starts with a good soaking. The coffee beans are placed in vats of very hot water (near boiling point), which removes most of the compounds – caffeine, flavors, essential oils and micro-nutrients.

    Once this is done, the beans are set aside and they use the same chemicals mentioned above to eliminate the caffeine from the water in the vats. The final stage is putting back the beans in the now caffeine-free water and left to absorb back flavors and essential oils.

Is decaffeination safe?

Experts say that both methods are safe, as steaming water is used to eliminate residual chemical particles. And, in any case, most chemical residues will largely disappear during the roasting process. 

There is a possibility that your decaf still contains chemical agents, but health officials insist the amount of solvent is very low and poses no health risks.

Non-solvent-based decaffeination methods

The most popular non-solvent based decaffeination methods involve water and carbon dioxide (CO2). Green coffee beans are again left to soak in water for hours, then they pump carbon dioxide at high pressure and temperature. CO2 acts as a selective decaffeination agent and only extracts caffeine molecules, leaving flavors and aromas intact.

Finally, there is the so-called Swiss Water Process, which also involves soaking the beans. The first batch of beans is removed and a charcoal filter is used to trap caffeine molecules. A new batch of coffee beans will be placed in the same water – and this is the interesting part. 

Since the water is already saturated with flavors and oils, the new batch of beans will only lose caffeine molecules.

This is the safest method and allows beans to retain their original flavors. It is also an uncommon method, only used for a few types of organic coffee.

So as we’ve seen, there are quite a few ways to decaffeinate coffee. Has this lesson in decaffeination made you more or less likely to drink decaf?

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Sources

Decaffeination 101: Four Ways to Decaffeinate Coffee
https://coffeeconfidential.org/health/decaffeination/

Decaffeination Process: Essential Facts
https://soloespresso.net/the-decaffeination-process/