Dark Roast Coffee:
The key factor in determining the kind of roast of a coffee bean is the temperature at which it is roasted. Dark roast coffees come from a bean that is darker in color because it has been roasted at a hotter temperature, usually about 240ºC. For reference, a light roast would be roasted at around 180-200ºC. The longer cook time and increase in temperature makes a dark roast bean less caffeinated than a lite roast and will yield a coffee that is more one dimensional in flavor.
The longer cook time and increase in temperature makes a dark roast bean less caffeinated than a lite or medium roasts and will yield a coffee that is more one dimensional in flavor. The dark roast coffee will taste more bitter and chocolaty, and even a little burnt. Part of the reason the taste is less complex is because the array of flavors in the bean are cooked out or overshadowed by the intense roast of the bean. Dark roast is generally heavier in taste and has a more “coffee feel” than lighter roasts which tend to taste more acidic and herbaceous.
If you want a richer and more true coffee flavor, dark roast coffee is definitely the way to go. Even though it has less caffeine than a lighter roast, it packs more intense flavors that are more traditionally associated with coffee.