Which coffee has more caffeine? Here’s the abbreviated answer: It depends.
Let’s dispel the most common myth right off the bat: A dark-roast bean contains more caffeine than a light-roast bean due to its stronger flavor. Not true. Actually, the caffeine content in both is virtually the same. An opposing view held by many is that the darker the roast level, the lower a bean’s caffeine since much of it is lost or "burned off" during roasting. Yet caffeine changes very little during a roast. Any significant variation would require a roasting temperature above 600°F. Since temperatures rarely exceed 470°F, a bean’s caffeine remains relatively static across all roast levels.
But wait. Even though a bean’s caffeine content changes little during roasting, a bean’s caffeine per volume and per weight is altered considerably—not because the caffeine changes but because the size and the weight of the beans change. The longer a bean is held in the roaster, the darker in color, lighter in weight, and larger in size it becomes. ...
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