The roast is the unleashing of all the efforts that the many growers and Mother Nature have hidden in their fruits seedlings. Different growing conditions; soils, shade, rain, sun etc. play a part in the beans final cup, but all go use less if not brought together and released by the heat of the roast.
There are many styles of roasts in the world, they vary from extremely light roasted to very dark black and oily. Each varied scale of color has a name to denote it, such as American, Cinnamon, New Orleans, Half City, Full City, Italian followed by the term roast. I use just two terms to define our roasts, Viennese and French.
Our Viennese will be brown in color and finished with the oil just leaking out but likely to hide barely out of sight under the outer shell of the finished bean. I look to bring the tastes of the growing conditions that are hidden in the bean to come forward in this style (the brightness of a crisp Colombian) but still having the aroma of smoke to add sweetness and flavor. Viennese roasts will cover some of the light tastes that I do not prefer in the cup. Earthy and raw musty flavors come to mind. I often refer to these tastes as having coffee with the unwashed. Not good. A nice Viennese roasted coffee will be excellent with many morning and mid day foods and sweets.
French roast is not possible on all beans. The bean will be held in the roaster for a greater amount of time. One of the growing conditions that effect how the bean will roast is the altitude at which it is grown. The higher altitude beans (3200 feet and above) are known as SHB (strictly hard bean) and will handle the longer time and higher heat the roaster will apply to it. Longer time in the roaster further caramelizes the sugars to a darker brown and continues to pull the oils out of the bean, when the oils hit the hot steel drum they create smoke that the bean absorbs and add to their taste. If this is done with the right touch, the full rich taste that the bean has hidden inside will be acknowledged.