The process of adding heat to coffee sets off a chain reaction known as the Maillard Reaction. Sugars are broken down, chlorogenic acids are degraded and aromatic oils develop. It is this process that releases the flavour and aromatic compounds in coffee and gives coffee its colour. The flavour profile can be adjusted by controlling the temperature and duration of the roast, which are essentially the two main variables at play in coffee roasting. The flavour will also depend heavily on the coffee beans used (known as ‘green’ coffee), and in practice, a blend will often include a range of different beans to achieve a desired flavour profile.
A coffee roasted for a long time at a low temperature will bring out an intense sweet flavour to the coffee (like our Café Express Italian blend). A coffee roasted for a short time at a high temperature will bring out a bright acidic flavour to the coffee. Coffee is also roasted to a specific colour measurement. A light coffee will produce a thin citrus cup, a medium coffee will produce a smooth well rounded cup, and a dark coffee will produce a strong heavy bodied cup.