Decaffeinated Coffee, How Does it Work?
Sometimes you just want a cup of coffee without having to deal with the caffeine. Luckily, you can turn to decaf. But how do you take the caffeine out of a coffee bean? In a better world we'd just wave a magic wand and the caffeine would vanish. Here, however, we're stuck with plain old chemistry to do the work.
There are several different ways to remove the caffeine and put the flavor back in. The basic process starts with exposing the unroasted (green) beans to near-boiling water. This extracts the caffeine. Unfortunately it also extracts the flavor oils and compounds that give coffee its rich taste and body. The trick is to filter out the caffeine from the oils, and then put the oils back into the beans. Still sounds pretty magical to me.
Here are the main decaffeination methods in use worldwide today:
European Process (also called KVW): Beans are soaked in hot water, then set aside. Methylene chloride solvent is added to the water, where it bonds with the caffeine. The resulting solid compound is skimmed from the surface of the water, and then the beans are returned to the liquid to reabsorb the oils left behind.
Ethyl Acetate Process (also called Natural Decaffeination): Same basic method as European, but the solvent is a naturally-occuring compound found in many fruits, such as bananas and apples. Coffees labeled “naturally decaffeinated” probably used this process, even though the actual solvent used was likely synthetic Ethyl Acetate, rather than that gathered from a ton of fruit.
These methods generally result in a nicely flavorful coffee, and many decafs offered currently use one of these.
Swiss Water Process: The beans are soaked in hot water, which is then filtered with activated charcoal to remove the caffeine. This method tends to damage more of the flavor compounds than the chemical processes, so the coffee is sometimes flatter-tasting. This effect is somewhat mitigated by using water that has been pre-saturated with oils from a batch of beans which are soaked and then discarded. This may have the potential for transferring flavors from one batch to the next, which is not ideal if you want to preserve a particular regional coffee taste.
Mountain Water Process: Similar to the Swiss process, this facility uses glacial water from the Pico de Orizaba mountain in Mexico. However, the water is not re-used for subsequent batches. This results in a lively and flavorful cup of decaf, nearly on par with premium caffeinated coffee.
The additional costs of shipping and processing beans into decaf are partially offset by the side market of selling the extracted caffeine. Ever wonder where energy drinks get their buzz? From your bag of decaf beans, that's where!
Historically, decaf has a reputation for being bland and thin. This is because in the past not as much effort was put into using great beans and really working to restore the full coffee flavor. The decaf market was considered a secondary one. The new influx of micro-roasters and interest in a wider variety of coffee offerings has resulted in the decaf market upping its game. Premium beans go into the processing facilities, and premium decaf beans come out. But the challenge is not yet over.
One side effect of the decaffeination process is that the green beans have a shorter shelf life and a more finicky roasting profile. It takes a delicate balancing act on the part of the roastmaster to bring out the best flavors in each batch. We drink a ton of decaffeinated coffee here at Night Owl Roasters, so it's very important to us that we produce the best-tasting decaf roast possible. After much experimentation, we think we've found it in our Decaf Blend, a mix of Indonesian and Central American beans decaffeinated with the Mountain Water Process. It's full-bodied and tastes great. Give it a try the next time you want a gentler cup of brew.