Lighter roasts are brighter and fruitier in flavour. The roasts tend to be a bit more acidic, but with the light roast, the bean’s natural flavours play a larger role, unbiased by any extended roast in which subtle notes are lost. Light roasts tend to be more expressive, bright, and acidic.
Medium roasts are darker and more brownish in colour compared to a light roast. This roast allows the bean to take on more of the roasting process flavour in addition to retaining its original taste. A medium roast tends to be more balanced with regards to acidity and will result in a fuller-bodied coffee. Overall, a medium roast protects much of the bean flavour while also offering a nice balance with the roast flavour, all while muting the acidity. For many, this isn’t a compromise, but instead, the best of both worlds.
This roast is easy to identify with dark oily beans that have a distinct sheen. The roast brings all the oils from the beans to the forefront leading to a robust and slightly charred flavour. Sometimes a dark roast will have an almost burnt flavour. In most other contexts, the term burnt would normally be negative, but millions of coffee lovers desire this quality in their coffee because it adds a potent accent to their experience. Dark roasts are usually the least acidic, but the downside here is that many of the original qualities of the specific bean are lost. If you want to fully experience the nuances of a bean, you’re better off going with a light or medium roast.