Coffee beans are naturally full of caffeine, so to sell decaffeinated coffee, the beans have to have the caffeine physically removed from them (at least as much as possible). So how is this not-so-modern marvel accomplished?
There are actually four ways coffee roasters can decaffeinate their blends: a direct method, an indirect method, a water process, and a supercritical process.
First, roasters soften green coffee beans with steam, and then they apply a solvent that literally bonds to caffeine molecules directly to the beans. They then rinse the beans, effectively washing away both the solvent and the caffeine.
There are different types of FDA-approved solvents for this method, but the only one that can claim the label of “naturally decaffeinated” is ethyl acetate, which occurs naturally in some fruits.
The indirect method also uses a caffeine-removing solvent like the direct method, but in this case, the solvent is not applied directly to the beans. The beans are first soaked in water, which extracts the water soluble caffeine. The beans are then removed from the water, and the leftover water is treated with the solvent.
Why bother treating the now caffeinated water? The water also removes many flavor compounds and oils from the beans during the soaking step, so the decaffeinated water must be reintroduced to the beans so the beans can reabsorb these missing compounds.
The water process is very similar to the indirect method, except that instead of treated the caffeinated water with a solvent, the water is run through a filter to remove the caffeine. From there, the water soaks the beans once more, giving back the flavor compounds they removed from the initial soaking process.
This process starts similarly to the direct method in that the coffee beans are first steamed to soften. The steamed beans are then placed in a container under high pressure with either liquid carbon dioxide or liquid oxygen, which act as solvents to extract the caffeine molecules. As the container’s pressure drops, the liquid solvent becomes a gas and evaporates, taking the caffeine with it. Since the flavor compounds are larger than caffeine molecules, they do not evaporate and remain with the beans during the entire process. Because the flavor compounds never leave the beans, many experts and connoisseurs insist that this method creates the best flavor for decaf coffee.
However, there is no real way of knowing which method decaffeinates your particular flavor of brew, as no roast has their particular method on their labels. But decaf drinkers, you can be assured that no matter the decaf process, your coffee beans are quite caffeine-free and will not give you the jolt you wish to avoid.