Dark roasts have more caffeine, right??

One day in the office, when I still worked in one, I heard 2 coworkers talking about drinking dark coffee and how the darker roast will really get them buzzing, surmising incorrectly, that darker roast coffee has more caffeine. It is a rather common belief that the darker the roast, the more caffeine. Bolder flavor, bolder buzz. This will surprise many, but that is not the case. In the roast process, the green beans are roasted to levels that range in color from a cinnamon brown to chocolate brown, to black. In that process, the beans are headed in a rotating or spinning drum to ensure a uniform roast. While this occurs, moisture is removed from the beans and the light covering of the bean and the light covering of the bean is removed creating chaff. As the moisture is removed, so is the weight and density of the bean. The resulting darker roast will certainly present with a bolder flavor and presents as darker in the cup, but the overall caffeine is marginally less. More about roast levels on a future post.