Claim: Does dark roast coffee have more caffeine than light roast?

The claim that dark roast coffee has more caffeine than light roast is mostly false. Research from sources like Healthline and Peet's indicates that dark roasts generally contain slightly less caffeine than light roasts when measured by weight. However, some sources, such as CoffeeGeek, argue that darker roasts can have higher caffeine percentages due to mass loss during roasting. This discrepancy arises from different measurement methods and interpretations of caffeine content in coffee beans. Overall, the consensus leans towards light roasts having more caffeine than dark roasts when compared accurately. The models diverge sharply — treat this as higher-uncertainty. Gemini comes in highest (50%), while OpenAI is lowest (25%). Perplexity expresses higher confidence than Gemini on this claim. While some sources claim that dark roast coffee has more caffeine due to its density and bean expansion, this does not universally apply. The evidence suggests that when measured by weight, light roasts typically have higher caffeine content. The conflicting information from CoffeeGeek, which states that dark roasts can have a higher caffeine percentage, introduces uncertainty. However, this does not significantly alter the overall verdict, as the majority of reliable sources support the idea that light roasts generally contain more caffeine.