How is Coffee Roasted? An Inside Look
Every wondered how your favorite coffee is made? Or why some coffee roasters seem to make better coffee than others?
Coffee roasting is part art and part science. But it can be summed up basically in this way: heat over time.
Raw coffee beans are similar to other raw foods that we must cook and prepare. If you cook something in your oven, you preheat it, take care to cook the inside as well as the outside in a timely manner, and make sure the outside has the look and finish you are going for.
Coffee beans develop their flavor through internal pressure, and outer caramelization. They are prone to roast defects, such as craters and pitting. These are caused by the same internal pressure that helps produce good flavors in the first place. Therefore, there is a balancing act of building internal pressure while maintaining the integrity of the beans through the roasting process.
Some roasters want to take a nice long time to slowly develop flavors. This keeps beans from having defects while allowing roasters to go quite dark. It may inhibit certain flavor-producing chemical reactions from occurring, however, as well as bake some inherent flavors out of the beans.
Some roasters like to blast through roasts as fast as possible, without getting defects. This will produce acidic and fairly "clear" coffee, characteristic of Third Wave roasters who like light roasts with forward, acidic, fruity notes.
Many roasters are hybrids of these methods, or use different methods depending on the bean and how dark they want to roast it.
Roasting begins with the pre-heating. The amount of heat you begin with determines how fast you will roast. It also determines the beginning internal pressure, because the initial heat will immediately begin working its way into the bean. To high of a temperature at the beginning will cause defects, or cause a very fast roast that will lack certain flavor qualities. Too low of a temperature, and you will have trouble cooking the inside of the beans.
Roasting is then about the temperature over time. Coffee roasting times vary greatly. Common time ranges might be 8 minutes to 15 minutes. Often, smaller roasters will roast much faster, while large commercial roasters will be longer roasts.
Extending roasting times generally will lead to more caramelization and more body. This means it will feel heavier, perhaps more syrup-like, and taste more robust. This is not always a good thing, and needs to be balanced with sweetness and acidity.
Roasting fast will increase acidity and sweetness, at the expense of body and caramelization.
As you roast over time, the acceleration of the roast will decrease. This means the temperature will increase more rapidly at the beginning, and begin to slow throughout the entire roasting process.
Beyond this, different beans will require slight modifications to get similar roasts. Even the same beans, because they are natural products harvested in other countries, subject to variations in weather, soil nutrients, shipping and storage, and the time of year, will require roasting modifications bag to bag, shipment to shipment.
The final aspect of roasting is the finish. How dark do you want to roast? and How long do you want to take to achieve that color?
Since this is the end of the roast, we must be careful not to achieve our final color too fast. This will mean that the outside of the bean is cooking faster than the inside. However, if we go too slow at the end, we will cook out all the nice flavors we have been trying to develop.
Once that is done, we will drop the beans from the drum onto a cooling tray and cool them as fast as possible to stop the roasting process from continuing.
While you can immediately begin looking for defects on the bean's surface, or taste them in a cupping, it will take a few days for the bean to taste how you want. During roasting, beans begin to release gas, and this continues well after roasting. These gases give coffee an off taste, someone carbon-y and woody, but this taste goes away with degassing after a few days.
Here at Coffeyville Coffee Co., this is just the beginning of what goes into our roasting process and philosophy. We are dedicated to consistent and delicious coffee, worthy of the title of America's Heart of Coffee. Our roasting techniques ensure consistently delicious coffee, no matter what variety or blend you choose. For that reason, we are so happy to be your choice of coffee every morning.