As a coffee connoisseur, you know that there are a wide variety of roasts of coffees, varying in color, from Starbucks’ new Blonde Roast to the very dark Spanish Roast. But how are these darker and lighter coffee roasts created?
It’s actually a simpler process than you might think. All coffee beans start out as “green” coffee beans, and they actually have a slightly green color. When coffee beans are originally shipped to roasters, this is how they are shipped–green. The roasters create the darker colors by the temperatures implemented in the roasting process. The higher the temperature, the darker the roast.
There are specific names for roasts that are determined by the different temperatures used for the roast. For example, the Arabian roast, one of the lightest roasts, comes from roasting the coffee beans between 165 °C (329 °F) and 210 °C (410 °F). French roast, one of the darkest roasts, is roasted at 240 °C (464 °F).
The darker roasts also affect the feel of the beans and the caffeine content as well as the taste. The darker the roast, the more full-bodied and bitter (stronger) the taste is. However, once temperatures go beyond the high temperature for the French roast, like in the Italian and Spanish roasts, the taste actually thins out a little bit since the higher temperatures burn off the acidity.
Darker roasts make coffee beans oilier, which affects the taste, and roasting beans at high temperatures reduces the amount of caffeine contained in the beans. The lighter the roasts, the higher the caffeine content. Note, though, that this reduction isn’t too significant. Light roasts typically contain 1.37% caffeine levels, whereas dark roasts contain 1.31%