Green coffee beans are added to the roaster and the beans are tumbled at high heat until processed to the desired level. During this process the bean goes through different stages. First the heat evaporates any water in the bean. The beans then start to swell, sometimes to twice the size of its green bean state. Cracking then occurs and the skin of the bean comes off. The color of the bean changes from green to yellow, then to a yellow-brown to light brown and then to a dark brown (the color is determined by the roast desired). As the bean roast longer, more oils are released from the bean, so that a dark Italian roast bean will be oilier in appearance than a City roast coffee.
Listed below are the most common types of roasts achieved:
Roasting time is approximately 7 minutes resulting in a coffee that has a subtle light flavor and body. Types of coffees using this roast may be referred to as – New England Roast, Half City Roast and Cinnamon Roast.
Roasting time is approximately 9 to 11 minutes resulting in a coffee that has a balanced body and flavor. These roasts are referred to as Breakfast Roasts, American Roasts and City Roasts. American Roasts are roasted closer to 9 minutes, while the City Roasts are a little darker generally roasting for closer to 11 minutes.
Medium Dark Roasts
Roasting time is approximately 12 to 13 minutes resulting in a coffee that has a more robust flavor than the Medium Roasts. These roasts are referred to as Full City Roast, Vienna Roast, Continental Roast and French Roast. Full City Roasts are closer to 12 minutes while the French Roasts are roasted up to 13 minutes. These roasts are oilier in appearance than Medium Roast Coffees due to the longer roasting time. The Full City Roast is darker than the City Roast with chocolate notes; the Vienna Roast is roasted a little longer and has a robust flavor with spicy, chocolate notes; Continental Roasts are a longer roast with a full body and spicy notes; and the French Roast is a dark roast bean with lower acidity, and a very full flavor that is sometimes used for espresso coffees.
Roasting time is approximately 14 minutes resulting in the darkest coffee beans that are oily and have a full flavor. These roasts are referred to as Italian Roasts or Spanish Roasts. Italian Roast s are similar to French Roasts but are slightly stronger with a more burnt flavor. Spanish Roast is the darkest roast available with a dark, oily bean and a strong taste that has charcoal undertones.