If you think decaf coffee is actually free from caffeine, think again. USDA regulations require decaffeinated coffee to be just 97 percent caffeine-free, so you’re looking at about three percent in your cup to decaf. And some decaf brews have more caffeine than others. Generally speaking, Robusta beans will have more caffeine left after the decaffeination process than Arabica beans. Also, the longer than coffee is brewed, the more caffeinated it is– so if looking to avoid caffeine, opt for a blend that brews quickly. You should also choose a coffee that was processed using the Swiss Water method, which can remove 99 percent of the caffeine from the beans.