Is caffeine destroyed by roasting?

The relationship between roasting and caffeine is one of the most persistent myths in the coffee world. Many drinkers assume that because dark roasts taste more intense or 'stronger,' they must contain more caffeine, or conversely, that the roasting process 'burns off' the caffeine. In reality, caffeine is a remarkably stable molecule with a melting point well above the temperatures reached during standard coffee roasting.

During the roasting process, green coffee beans lose moisture and expand significantly, which changes their density. If you measure your coffee by volume—using a scoop, for example—a dark roast will be less dense than a light roast, meaning you are putting fewer actual coffee particles into your brewer. This is why a scoop of dark roast might yield slightly less caffeine than a scoop of light roast. However, if you measure by weight, the caffeine content remains nearly identical across the roast spectrum.

While some studies suggest that very high temperatures or extended roast times can lead to a tiny, often negligible, reduction in caffeine, these losses are not enough to impact your daily cup in any meaningful way. The chemical structure of caffeine is robust enough to survive the Maillard reaction and the physical transformations that turn a grassy green seed into a fragrant, brown coffee bean.

In practice, this means you should choose your coffee based on the flavor profile you enjoy rather than the caffeine content. Whether you prefer a light, acidic roast or a dark, chocolatey one, the caffeine hit will be largely the same. If you are looking to manage your caffeine intake, focus on your brewing method, the dose of coffee used, and the total volume of the beverage rather than the roast level on the bag.