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The truth about decaf

August 06, 2015
Jeff Yang
Educational Series

A question I get a lot at the roaster is how I decaffeinate my beans. Well, I don’t. Decaffeination is something that is done only to unroasted (green) coffee before it is delivered to a roaster. I source decaffeinated coffee in the same way as my other offerings—tasting and deciding among several options. A caveat is that decaffeination is a very involved process, and always adds an additional cost to a bean. Like any coffee, the trick is finding something that is both delicious and a good value.


There are a few ways that the alkaloid caffeine can be removed from a coffee bean. No single method is capable of removing 100 percent of the caffeine, so the safest thing for anyone with an allergy or other dangerous caffeine sensitivity is complete abstinence.

First, and most common, is the ‘conventional’ or ‘direct contact’ method. This involves a caffeine-bonding solvent being directly applied to the raw coffee and then removed with a catalyst. This is by far the most cost effective of the methods but it has become less popular due to the stigma associated with the use of chemicals. If a roaster doesn’t clarify how their beans have been decaffeinated, it is safest to assume it is a conventional decaf.

The second most common would be what is called ‘water process’ decaffeination. There are only a couple facilities in the world where this is done, and the specifics of the method are carefully guarded secrets. This exclusive and proprietary element adds a very high cost when compared to conventional. I only buy and roast water process decaf for Cartel because I believe it not only ‘feels’ healthier but also tastes better.


Green coffee is placed into water long enough to remove all of the water-soluble solids. The coffee used to make this ‘green coffee soup’ is discarded (another reason this method is quite pricey) as it is now missing not only its caffeine, but all other flavor creating elements which are desirable. 

This soup is then passed through a filter calibrated to isolate and remove the caffeine from the other dissolved solids. By the way, this filtration is where those trade secrets I mentioned happen. So now you have a vat of decaffeinated, unroasted coffee solids dissolved in water. The next step is my favorite.

Another batch of green coffee, equal in size to the discarded one, is added to this soup. Since the soup is a saturated solution of all the coffee solids except caffeine, it pulls only caffeine from these new beans through osmosis, leaving the other solids associated with flavor and aroma intact. These new beans are then removed and dried for shipping to a roaster.


Pressurized carbon dioxide can also be used to remove caffeine from green coffee, but it is not (yet) nearly as cost effective as the water process. There have also been cultivation experiments involving the selective breeding of varieties with a lower caffeine yield. The problem here is that caffeine’s sole botanical role is to be a natural insecticide for the coffee plant. When this is removed, the plant loses its most important defense and, ironically, requires some sort of applied chemical to survive.


Removing caffeine from coffee is challenging work and it is really not possible without compromise on some level. Still, it is something that anyone else who may be wired like me can appreciate. I have a very high sensitivity to caffeine and on the occasion that I am in the mood for an evening cup, a good quality decaf is a godsend.