Roasting the Coffee Bean

Nearly all coffee sold in the world is sold to the consumer roasted. Roasting coffee beans causes chemical reactions, which create and affect flavour components in the coffee. In the first stage, the green beans are heated until they turn yellow in colour, and start to smell like popcorn. The second stage is called the "first crack", where the beans are heated to 205°C. During this stage, the beans turn a light brown colour, double in size and experience 5% weight loss. During the next stage, the temperature is raised to 220°C, and beans darken further. The "second crack" happens when the temperature is raised to 225-230°C, and the bean takes on a much darker colour and an oily sheen. The darker the colour of a roasted bean, the greater the level of caramelisation of sucrose, and the oilier the bean. Typically there are six grades of roast.

Cinnamon	A very light roast
American	Light to medium roast, offering a medium bodied coffee
Viennese	Medium roast, some beans with an oily sheen. Sugar have caramelised to offer a balanced cup, with good aroma and acidity
Italian	A dark roast, providing deep, rich flavours with a good crema, sugars in the bean at this point are carbonised, offering some charcoal notes. Italian Coffee roasts are available from a wide variety of suppliers
French	Almost black roast, strong and full bodied with an smoky flavour
Espresso	Darkest and oiliest of the roasts, with a strong and heavy flavour