How Decaffeinated Coffee Is Made

Julia 16

Today I found how caffeine is removed from coffee to produce the decaffeinated version of the world’s most popular drink.

There are several different methods used that can make coffee relatively decaffeinated. The drawback (or advantage, depending on your preference) of all of these methods is that they generally make the coffee flavor milder due to caffeine being one of the components which gives coffee its bitter, acidic flavor.

The general decaffeination processes includes soaking the still green coffee beans in hot water (160-210 degrees Fahrenheit) and then some sort of solvent or activated carbon is used to extract/dissolve the caffeine. The solvents typically used are methylene chloride or ethyl acetate. Unfortunately with this process, the first batch of beans loses most of its flavor to the water and is often thrown out. However, once the dissolving liquid is saturated from the first batch, the subsequent batches retain much of their flavor.  In some methods, the coffee beans from the first batch will be re-soaked in the water solution to reabsorb some of the flavor compounds, minus the dissolved caffeine, so that they can eventually be used for making decaffeinated coffee.

The first such process, as described above, for decaffeinating coffee was invented by Ludwig Roselius in 1905. This method used benzene, a potentially toxic hydrocarbon, to remove caffeine from presoaked green coffee beans. Coffee was steamed in brine and then benzene was applied to the beans. Nowadays, this method is considered unsafe and no longer used.

Another method is where the beans are steamed for half an hour, rather than immersed in water, and then rinsed with solvents – ethyl acetate or methylene chloride to extract and dissolve the caffeine from the beans. Ethyl acetate is an ester that is found naturally in fruits and vegetables such as bananas, apples, and coffee. The solvent is first circulated through a bed of moist green coffee beans and then recaptured in an evaporator while the beans are washed with water. After the chemicals are drained, the beans are steamed again. Usually the solvent is added to the vessel, circulated and emptied several times until the coffee has been decaffeinated to the desired level. The coffee is said to be ‘naturally decaffeinated’ when ethyl acetate derived from fruit or vegetables is used. The advantage of using these solvents for decaffeinating, is that they are generally more precisely targeted to caffeine and not other components that give coffee its distinct flavor. Up to 96% to 97 % of the caffeine from coffee can be extracted this way.

Another method, is known as the Swiss Water Process  and employs a charcoal filter. The charcoal is normally used in conjunction with a carbohydrate solvent (highly compressed CO2 ) so only the caffeine is absorbed. In this method, first, the green coffee beans are soaked in hot water and then the first batch of coffee beans is discarded. The caffeine is then stripped from the solution by activated carbon filters.  This leaves the solution saturated with flavor compounds which is then reused to soak a new batch of decaffeinated green coffee beans. This method extracts up to 98% of the caffeine. Carbon dioxide is also a popular solvent because it has a relatively low pressure critical point.

Another method known as the sparkling water decaffeination process is similar to the CO2 method, but instead of removing the caffeine with activated carbon filters, the caffeine is washed from the CO2 with sparkling water in a secondary tank. This type of solvent consists about 99.7% compressed carbon dioxide and 0.3% water.

Bonus Facts:

  • The coffee industry in the United States alone is valued at about $19 billion annually.
  • It takes five years for a coffee tree to reach full maturity. After that, each tree bears 1-2 pounds of coffee beans per growing season.
  • A six-ounce cup of coffee typically contains approximately 50 to 75 milligrams of caffeine. This amount varies depending on the method of preparation and the type of coffee. Unfortunately for people who are sensitive to caffeine, as little as 10 milligrams can cause discomfort making caffeinated coffee unpalatable for them.
  • There are 1,200 different chemical components in coffee with more than half of them contributing to the flavor of coffee.
  • Decaffeinated coffee still contains a small amount of caffeine, thus decaffeinated coffee is not technically caffeine-free.
  • Today, decaffeinated coffee accounts for approximately 12% of total worldwide coffee consumption.

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16 Comments »

  1. Sherrie Miranda January 20, 2013 at 12:40 pm - Reply

    I can’t believe they go through all this, then charge the same price as regular coffee. Is this what is causing the rise in coffee prices.
    Personally, I would rather stick to the pure stuff and use a bit less.
    I also understand that the darker the coffee, the less caffeine it has. Supposedly, more caffeine gets burned off the longer it is in the sun (or wherever). Do you know anything about this?
    Thanks,
    Sherrie

  2. Ed May 21, 2013 at 4:10 pm - Reply

    The most popular drink in the world is not coffee but tea..

    • Daven Hiskey
      Daven Hiskey May 21, 2013 at 5:00 pm - Reply

      @Ed: sources?

  3. Sherrie Miranda May 21, 2013 at 5:04 pm - Reply

    Ed,
    I really doubt that. Are you English? The English drink tea more than coffee, but I have been to more than 15 countries and England is the only place I was offered tea instead of coffee. I enjoy a good cup of English tea, strong with honey and milk. Not much into the herbal teas though.
    What about my questions (above)?

  4. Christine May 25, 2013 at 6:24 am - Reply

    I live in England, but I am an American, and it seems like tea is the most popular drink in the world, but in reality coffee is. I drink decaf coffee, and even after three cups I feel some trace of caffeine. It must still be inside the drink, caffeine that is.

  5. Yer Pal July 23, 2013 at 12:23 pm - Reply

    Ed may be onto something. All over Asia tea is immensely popular. A billion Chinese people might take issue w/ this argument.

  6. Sherrie Miranda July 23, 2013 at 1:12 pm - Reply

    Yes, Asians drink tea, but with the exception of Great Britain, coffee is the choice in the rest of the world. Maybe Argentina is also an exception as they like that strong tea that I seem to have forgotten the name of. (If you watch “Motorcycle Diaries” the two guys drink it to stave off hunger.) My friend swears that is how she has maintained her weight all these years while others around her are all gaining.

  7. teacoffee August 19, 2013 at 9:35 pm - Reply

    lets all argue about tea!!!raaah

  8. mickey September 4, 2013 at 3:40 pm - Reply

    http://en.m.wikipedia.org/wiki/Tea

    “after water, tea is the most widely consumed beverage in the world.”

    I know it’s just Wikipedia, but a slightly more solid source than “where I live people sure seem to drink a lot of X!”

    just saying.

  9. Sherrie Miranda September 4, 2013 at 10:06 pm - Reply

    Even Wikipedia won’t convince me. Latin Americans drink coffee; Canadians & Americans drink coffee. Europeans drink coffee. The English, Chinese and Japanese drink tea. The rest of the world tends to be kind of split in half: many people drink tea and many drink coffee.
    I know China is large, but NOT that large.

    • THQ November 27, 2013 at 2:29 pm - Reply

      The vast majority of Asia drinks tea rather than coffee, including the Chinese and Indians.

      World population = 7.1 billion
      Asian population = 4.3 billion
      Non-asian population = 2.8 billion

      That’s why tea is more popular and the global production of tea dwarfs that of coffee because tea drinkers on average drink more tea than coffee drinkers drink coffee. I’m an average coffee drinker and I have an average of 2 cups a day. Sure there are wired people who have 20 cups but they are outliers.

      The average tea drinker, especially in Asia, drinks far more than that. In China, for example, green tea is basically drunk like water at meal times and at work, most people have a refillable tea thermos on their desk. Green tea has far less caffeine being the reason why this is possible.

  10. Jake Lakota September 12, 2013 at 10:25 am - Reply

    Now I want to start the fight is Espresso more caffeinated than regular coffee. Have at it

    • Chris December 3, 2013 at 12:23 pm - Reply

      An espresso is just the shot of coffee that would go in to the hot water which makes it an Americano or “regular coffee”

  11. Sherrie Miranda December 3, 2013 at 1:26 pm - Reply

    As I mentioned earlier, the darker the coffee, the less caffeine, according to my understanding. I read that the longer the bean is roasted, the more caffein that gets burned off.
    I hope this is true as I love a strong coffee, but not so much the effects of caffeine. I do remember having an Islandic boyfriend many, many years ago though, that used to make expresso that had me buzzing for hours.
    Any concrete info on this would be greatly appreciated. ;-)

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