Roast degree is one of the most important indicators with the roast. It can be measured by a color meter or by tasting. Roasters usually want to enhance coffee’s own flavours and decide the roast degree. Typically light roasted coffees are more acidic, and dark roasted coffees are more bitter. Also fruity flavours are more common on light roasts, and roasty and burnt flavours are more common on dark roasted coffee. Light roasted coffee is more fruity due to high amounts of an organic compound, 5-hydroxymethylfurfural. When roasting goes further, this compound breaks down to less fruity compounds. The amount of sulfuric compounds increases, which produces roasty and burnt flavours. As a role of thumb, we can assume that light roasted coffee brings the character of the raw coffee out better. It is easier to discriminate light roasted coffee from each other than dark roasted coffee.
