Know your coffee roasts
Roasting is a heat process that turns coffee into the fragrant, dark brown beans we know and love.
Roasting brings out the aroma and flavor that is locked inside the green coffee beans. Beans are stored green, a state in which they can be kept without loss of quality or taste. A green bean has none of the characteristics of a roasted bean -- it’s soft and spongy to the bite and smells grassy.
Roasting causes chemical changes to take place as the beans are rapidly brought to very high temperatures. When they reach the peak of perfection, they are quickly cooled to stop the process. Roasted beans smell like coffee, and weigh less because the moisture has been roasted out. They are crunchy to the bite, ready to be ground and brewed.
Once roasted, however, they should be used as quickly as possible before the fresh roast flavor begins to diminish.
Light brown in color, this roast is generally preferred for milder coffee varieties. There will be no oil on the surface of these beans because they are not roasted long enough for the oils to break through to the surface.
This roast is medium brown in color with a stronger flavor and a non-oily surface. It’s often referred to as the American roast because it is generally preferred in the United States.
Medium dark roasts
Rich, dark color, this roast has some oil on the surface and with a slight bittersweet aftertaste.
This roast produces shiny black beans with an oily surface and a pronounced bitterness. The darker the roast, the less acidity will be found in the coffee beverage. Dark roast coffees run from slightly dark to charred, and the names are often used interchangeably — be sure to check your beans before you buy them!
article source: ncausa.org