Decaffeinated coffee – How the heck does that work?

Today’s question: Decaffeination : How does that work?

Here are a few caffeine facts to get started on.

Caffeine is a complex organic compound found naturally in many plants.

Typical decaf is 97% to 99% caffeine free.

A regular drip-brewed cup (8oz) of premium coffee (arabica) contains about 200 milligrams of caffeine.

Totally unbiased opinion here, of course, but in bang (literally) for the buck, not to mention the wonderful enhancement of your day, a cup of fresh premium coffee beats, hands down, any so called “energy drink” that you see someone slamming down with a grimace, and then smiling as the caffeine kicks in. Seriously people, life is too short not to enjoy the consumption of a wonderful fresh coffee beverage. Then you’ll get the smile of the enjoyment during and after the experience. Makes me crazy when I see those “energy drink” commercials. Not to mention that, if made at home, a great cup of fresh premium coffee costs about 25 cents per cup. Completely unbiased I am, of course.

My personal love of caffeine appears to be coming through a little bit here, and we did start out with a decaf theme, so, continuing on, how do you get rid of caffeine if you don’t want it?

You basically have two choices. You can decaffeinate using solvents or pure water. Hmmmm, tough choice. Pure water or paint thinner, which to choose? Seriously, on the “chemical extraction” side, the common solvents that are used to combine with caffeine include, dichloromethane, ethyl acetate, and (omg!) benzene. Although it is claimed that no traces of these lovely compounds remain on decaffeinated beans after the process, I personally can’t stand the thought that they ever touched my beautiful beans!
One of the main reasons that these chemical processes are so popular is that they allow the reclamation and repackaging of the caffeine for use in other products from Red Bull to Excedrin.
In general, in the chemical process, unroasted coffee beans are steamed, the solvent is applied, and the caffeine chemically attaches to the solvent, which is later treated with additional chemicals to make the caffeine drop out for reuse.
But, back at the beans, soaking in their little solvent bath, this process is repeated, until the desired 97% to 99% caffeine-free level is reached. Water is added and the beans are steamed for several hours “until the last of the solvent is removed”. At least that’s what they say.

On the pure water process side, no chemicals whatsoever are used, but due to nature of the process, the caffeine itself cannot be reclaimed for reuse, therefore, the process itself is more expensive. In a nutshell, water has the capacity to absorb caffeine on it’s own, along with soluble “flavor solids” present in the raw bean. In the pure water process, the unroasted beans are soaked in water, extracting a percentage of caffeine and also some of the flavor solids. The resulting caffeinated and flavored water solution is then passed through carbon filters which filter out the caffeine, but not the dissolved flavor components. Then, the beans from this original bath are thrown away. Yes, chucked out. Their mission in life was to produce a flavor solids rich, but caffeine poor water solution, which will be used in the next step of the decaf process.

The real secret in the pure water extraction process is in water’s ability to absorb only a given amount of dissolved flavor components. In the example above, the beans are exposed to repeated baths of water, but only the caffeine is removed by the carbon filters. At some point, the caffeine is fully extracted from the solution, but the dissolved flavor components remain, reaching equilibrium with the soluble flavor components in the bean, with the result that no more flavor components can be extracted. This is key when a fresh batch of beans is presented to the flavor rich, caffeine poor bath. Flavor components present in the new beans are not extracted because they are already in equilibrium with the flavor components in the solution, while caffeine continues to be extracted by the caffeine poor bath. Only the original beans (the thrown away ones) are used to create the flavor extract bath. The subsequent beans lose only caffeine to the bath. I find this idea of balance and equilibrium very appealing.

The most recognized pure-water process is known as the Swiss Water Process, or SWP for short. If you see “SWP Certified” on a bag of coffee, then you can be sure it was decaffeinated using a pure water process and no chemicals whatsoever. If it doesn’t say SWP it probably was chemically treated, since with that method the caffeine can be harvested (the profit motive is a strong one).

We have used SWP and only SWP processed decaf since the beginning, and wouldn’t consider using anything else (in case you couldn’t tell from the above).

So there you go. We love the power of informed choice!

John

Roastmaster

Dark Hollow Micro Roasters LLC
john@darkhollowcoffee.com

“Good Chemistry is more than a representation of a wonderful molecule.
It is the relationship we strive for with all of our customers.”

2 thoughts on “Decaffeinated coffee – How the heck does that work?

  1. John,

    Great description of what happens, though it does make me a little sad to think of all those original beans being thrown away. Is there anything they are good for? Also, does this SWP decaffeination usually happen near the source, or is this a process that is done stateside?

    Another question I’ve had is what kind of blend is your decaf? Reading how many beans get chucked with this process, I can see why I don’t ever see single origin decaf beans, but man do I wish I could have a nice cup of Guatemalan decaf!

    Thanks again for the interesting article,
    John

    • Hi John,

      Thanks for your comments and questions!

      The decaf process can happen before, or after importation to the U.S., and I don’t think it makes any difference as long as the process is the same.

      During our years of roasting coffee, we have seen a well established demand for decaf, and it is more than you might think. Although many people say there’s no point in drinking decaf since there’s no kick, I have also spoken to many where limiting caffeine was a necessity, but they sorely missed the taste of a good cup of coffee. We’re here for those people too.

      One of our favorite decafs this season is a single origin from Chiapas. The aroma coming off these beans within the first week after roast is enveloping, and is just as rich as full-on caffeinated beans. When we find a great bean / roast profile like this, it finds its way into blends with other complimentary beans/roasts. We do our Half-Caf with the Chiapas decaf beans blended with Guatemalan FTO beans (from Huehuetenango and simply wonderful in a medium roast).

      Thanks again for your great comments and interest in Dark Hollow!

      John

      @roasterjohn

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