The most common way to describe coffee roast levels is by the colour of the roasted beans, ranging from light to dark (or extra dark). As coffee beans absorb heat in the roasting process, their colour becomes darker. Oils appear on the surface of the beans at higher temperatures. Because coffee beans vary, colour is not an especially accurate way of judging a roast. But combined with the typical roasting temperature that yields a particular shade of brown, colour is a convenient way to categorize roasting levels.
Light roasts are light brown in colour, with a light body and no oil on the surface of the beans. This means that they retain more of the original flavours of the bean as opposed to the darker roasted coffee beans used in your average cappuccino. Light roasted beans typically have certain floral notes, berries or even chocolate. It’s also easier to distinguish between origins because a lot of the individual flavours have been retained.
Unlike medium or dark roast beans, light roast coffee engages your taste buds with a light, acidic, sweet taste full of beautiful floral notes. Light roasts also retain most of the caffeine from the coffee bean.
Light roasted beans generally reach an internal temperature of 180°C – 205°C (356°F – 401°F). At or around 205°C, the beans pop or crack and expand in size. This is known as the “first crack”. So a light roast generally means a coffee that has not been roasted beyond the first crack