How is Tea Decaffeinated? Tea Term of the Month: “Decaffeinated”

Decaffeinated teaDecaffeinated tea is a great option for tea lovers who wish to avoid much of the caffeine naturally found in the tea leaf.  All forms of tea (black, oolong, green, white, and pu-erh) can be decaffeinated; but really only black and green tea are regularly decaffeinated.  It must be noted that decaffeinated tea is NOT caffeine free.  The decaffeination process leaves a minute amount of caffeine in the leaf.  By law, tea labeled as “decaffeinated” must have less than 2.5 percent of its original caffeine level.   Currently, there are four methods of decaffeination: methylene chloride; ethyl acetate; carbon dioxide; and water processing.

Methylene chloride decaffeination is a process by which the molecules of caffeine bond to molecules of methylene chloride.  Caffeine is removed either by 1) directly soaking the tea in methylene chloride or 2) indirectly soaking the water (used to remove the caffeine) in methylene chloride and then returning the water to the tea for reabsorption of flavors and oils.  Because methylene chloride is widely believed to be unhealthy for consumption, a legal limit of 5 parts per million is placed on residual traces in the tea and the US bans all imports using methylene chloride.

Tea processed using ethyl acetate is often referred to as “naturally decaffeinated” because ethyl acetate is a chemical found naturally in tea. Caffeine is extracted in the same way as with methylene chloride processing, but ethyl acetate is the solvent.  However, ethyl acetate is very difficult to remove after the decaffeination process, and is sometimes described as leaving a chemical taste.

Carbon dioxide (CO2) decaffeinated tea is essentially “pressure cooked” with this naturally occurring gas. At high pressures and high temperatures, carbon dioxide reaches a supercritical state. The CO2 becomes a solvent with its small, nonpolar molecules attracting the small caffeine molecules. Since flavor molecules are larger, they remain intact, which is why this process retains the flavor of the tea the best.

Caffeine extraction with water is used primarily for coffee decaffeination, however a small amount of tea products are decaffeinated using the water method. After the caffeine is removed from the tea by soaking the tea in hot water for a period of time, the solution is passed through a carbon filter for caffeine removal. The water is then returned to the tea for reabsorption of flavors and oils.  This process is often described as “watering down” the flavor of the tea.

Arbor Teas offers organic decaffeinated teas that exclusively use the carbon dioxide (CO2) method.  We feel that this is the safest form of decaffeination, while retaining the greatest flavor and health benefits.  Try some today!

February 03 2010 02:30 pm | Tea Preparation and Tea Terms

11 Responses to “How is Tea Decaffeinated? Tea Term of the Month: “Decaffeinated””

  1. Dunrie on 09 Feb 2010 at 10:35 pm #

    So, I think I heard one time on the Splendid Table radio show on NPR that you can also decaffeinate tea “on the fly” by steeping it in water and then tossing the water after a handful of seconds. Apparently, the caffeine is really mobile and goes into the water first, and then other components in the tea come out of the leaves later, so if you toss the water after an initial steeping, you’ve gotten rid of most of the caffeine….

    Of course, now I don’t recall how long the initial steeping had to be for…

    Have you ever heard this?

  2. Aubrey on 14 Feb 2010 at 11:20 am #

    Yes, you are correct Dunrie! This “quick” form of decaffeination has been widely circulated throughout the tea industry. In fact, we offer a similar suggestion on our own website, However, we have recently come across new research by Nigel Melican, a respected “tea technologist,” who claims that this method (one he originally purported) does NOT remove as much caffeine as once thought. Nigel claims that up to 91% of the caffeine stays in the cup when using this method. We have yet to see the actual research so the jury is still out, but certainly something to consider.

  3. Tricia on 26 Aug 2010 at 10:04 pm #

    Now I’m curious: what happens to the caffeine (caffeinated water, caffeinated CO2) after it is removed from the tea [or coffee, for that matter]? Does it have another use, such as to amp up energy drinks? :^) Or does it just get dumped?

  4. Aubrey on 27 Aug 2010 at 9:25 am #

    Good question Tricia – Unfortunately, I don’t know the answer. But what a great idea for reusing it!

  5. Jayesh on 19 Dec 2010 at 1:42 pm #

    Chanced upon your website for the first time today.
    I am delighted to see a lot of good and informative posts here. Shall surely visit again.
    Keep up the good work!

  6. Chuck V on 26 Sep 2011 at 2:57 pm #

    I’m curious now about which is correct (i.e., where the science is on this)…does steeping for between 30-60 seconds and discarding that steeping eliminate most of the caffeine or not? Many references say yes, but you cite the one who now says ‘no’. I’m concerned that there doesn’t seem to be any real science behind any of these claims – since caffeine is water soluble, I’d expect a higher level than Nigel’s claim of only approx. 9%…but again I’m just guessing – seems easy to test – has no truly verified??

  7. Chuck V on 26 Sep 2011 at 4:23 pm #

    Found the following – that potentially answers my own question…here

  8. Aubrey on 27 Sep 2011 at 9:35 am #

    Hi Chuck -

    You found the source I was going to point you to! The article you site at chadao, is the article we refer to frequently.

    Happy reading – don’t forget to read the comments below the article as well. Many, many viewpoints.

    Arbor Teas

  9. Louise on 21 Oct 2011 at 12:28 pm #

    I had for a long time thought that brewing tea for 30 seconds would take away most of the caffeine too, and I looked into doing some caffeine testing after reading the posts here. They used to make a D+caf strip apparently but I can’t find it sold anywhere now. So the only available methods of testing for caffeine seem to involve using methylene chloride or ethyl acetate with a chemistry kit! Thanks for providing a great article on decaffeination. I also found this article, which covers a few other ways of decaffeinating tea.

  10. Whispering Pines Tea Co. on 20 Dec 2013 at 10:55 am #

    Energy drink companies account for the largest percentage of dehydrated tea caffeine, to answer that question :)

    Also, caffeine is water soluble, but is retained very deep in the cell structure of the leaf. You will get large amounts of caffeine even after you have completely extracted the flavonoids during steeping, and thus, steeping your tea for a short amount of time will not decaffeinate it. :)

    Great post!

  11. Tea, Glorious Tea: Best Decaf Tea Options - Life [Comma] Etc on 12 Aug 2014 at 8:39 am #

    [...] standard, cheaper store brands use (albeit “natural”) chemicals like methylene chloride and ethyl acetate which get the job done but leave behind low doses of chemicals that can disflavor the tea or make [...]

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