Whole Latte Love (which is an amazing site for buying coffee equipment that will answer any question you have before you purchase) has an interesting blog post up about how coffee becomes decaffeinated, which just happens to be something I’ve always wondered. As they explain:
In a nutshell, most decaffeination processes consist of soaking beans in water to dissolve the caffeine and then extracting the caffeine with either a solvent or carbon. This process is often repeated up to 12 times to obtain the most complete caffeine extraction. Some methods will actually use a coffee-flavored solution while soaking the beans to avoid a complete loss of flavor composition. Once the caffeine has been removed, the beans are then re-soaked in the decaffeinated water to reabsorb the flavor compounds that were lost in the initial extraction.
They even explain what happens to the excess caffeine they take out: They sell it to soft drink companies. Good to know.