How Coffee Gets Decaffeinated: Water Process

Feeling a bit jittery about how coffee is decaffeinated? Never fear: today we'll explain how some beans get stripped of their buzz using the water process, and how you can avoid those sleepless nights after your afternoon latte.

First, though, let's talk a little about the stimulant that drives so many of us to our local coffee bar every day. Caffeine is an alkaloid that naturally occurs in coffee plants as a pesticide: It serves to paralyze bug invaders, and gives off a bitter flavor as a warning of its toxicity.

Interesting side note: This often means that the more insect-resistant a coffee plant is, the more caffeinated it is. Robusta, or the low-altitude-grown, lower-quality species found most often in cheap commodity coffee blends, contains about twice the caffeine its cousin Caffea arabica does, making it less susceptible to infestation. (And also, generally less delicious.)

However, just like much of what is held inside our precious little coffee beans, caffeine is water soluble. That's why the water goes into grounds clear and clean and comes out brown and buzzing: The soluble material dissolves in the coffee at an extraction rate that's determined by things like the size of your grinds and the temperature of the water.


In order to decaffeinate coffee, the soluble caffeine needs to be taken out of the bean, while leaving as much of the delicious flavor intact. This can be done in several ways, but the best and most natural option (in my humble opinion) is a water-based process, as opposed to those that use chemicals.

In this method, the green, or unroasted coffee is fully submerged in filtered water that has been heated, in order to extract all the soluble material from the beans. The water solution is then filtered through carbon to separate the caffeine compounds from any of the aromatics that also came out during the extraction, and the coffee beans are then placed in an immersion tank with the caffeine-free solution, allowing them to reabsorb everything but the jitters.

Some standards worldwide require that the process of decaffeination eliminate 99.9% of the alkaloid from the coffee in order to bear the sleep-friendly label; others let 97% decaffeinated fly the fidget-free flag. Either way, the stimulating stuff left behind is, arguably, pretty negligible. (Though you might loudly disagree with me at 3 a.m., when your eyes are still wide open.)

Not sure whether you should take the risk? Drink plenty of water when drinking coffee of any type, as allowing yourself to get dehydrated will only emphasize the drink's invigorating effects. Eating something while imbibing can also slow the body's absorption of the alkaloid, which might be buffer enough to render your decaf cup as harmless as a kitten.

Are you super sensitive to caffeine? Do you find that even decaffeinated coffee gets you wired? (And are you sure it's not psychosomatic?)