Medium dark roast coffee starts to display the smoky flavor that appears in all coffees as the coffee fibers start to carbonize in the roaster. Darker roasts tend to have less acidity than lighter roasts, so if you’re looking for brighter flavors, a light roast or medium roast coffee bean might be more up your alley. If you’re looking for those smoky flavors to dominate everything, you’re more likely to be satisfied with our dark roasts.
Every coffee bean roasts differently, so there are no hard and fast rules with how long or how hot you’ll need to go in the roasting process to get your beans to medium or medium-dark. We classify coffee beans on both appearance and flavor, and when we say something is “medium-dark,” that usually means there’s a little oil on its surface and significant roasty flavor in the cup.
Roasting darker drives off water and the roasting process probably doesn’t actually get hot enough to degrade caffeine, so, if you’re measuring by weight, you might actually get a little more caffeine from medium-dark roast coffee than light roast coffee. That said, you’ll affect caffeine content way more by adjusting your brew recipe than by choosing any particular roast level, so it’s probably worth it to choose roast level based on factors like the flavors and level of acidity you prefer.