Coffee beans in their raw state (green) are subjected to heat for varying degrees of time to achieve the different types of roasts. This is known as the roasting process.
The Roasting Process
During the roasting process the beans pass through different stages. Firstly the water contained in the bean evaporates. Then the bean swells to twice its original volume which causes the silvery coloured skin to break and fall off (this is the chaff that is removed from the roaster at the end of the roasting process). The colour of the bean changes from light green to yellow, to yellow-brown, to light brown and then to dark brown. The coffee aroma develops from a series of chemical reactions as the bean is roasted. In its green form the bean has virtually no aroma.
There are many different roasts of beans available on the market but the following guide lists the main categories and their common names.
Dark Roasts (14 minutes)
The darkest roasts such as Italian Roast are also known as "Heavy Roast", with beans roasted nearly to jet black giving a smoky well roasted taste which masks the natural flavours of the coffee bean.
Medium Dark Roasts (12 to 13 minutes)
Medium dark roast is when the beans are roasted for a long time at a high enough temperature to bring the natural oil of the coffee to the surface.
Some examples of medium dark roasts are:
- French Roast - which is also known as "Dark Roast". French Roast beans are often used to make espresso.
- Continental Roast - which is slightly lighter than French Roast but with spicy body.
- Viennese Roast - which is roasted a little longer than regular American roast and has rich chocolaty body.
- Full City Roast - which is even darker than City roast.
Medium Roasts (9 to 11 minutes)
Medium roasts balance body with flavour.
Some examples of medium roasts are:
- Breakfast Roast - which is a bit sweeter than a light roast.
- American Roast - which is not as dark as any of the European roasts but has a good aroma.
- City Roast - which is darker than the standard American roast.
Light Roasts (7 minutes)
A light roast gives a very subtle light bodied flavour.
Some examples of light roasts are:
- New England Roast.
- Half City Roast.
- Cinnamon Roast - where the surface of the bean is dry with no oils present and flavour is light-bodied.