As the third wave coffee movement is bringing more information to the table regarding a coffee’s origin, it is only a matter of time until you will want to be more informed about roasting your coffee. Transparency has always been a part of Reggie’s Roast Coffee, sharing our story as Coffee Farmers and freshly roasting all of our coffee to order making sure you know your coffee is fresh. Roasting your coffee is a major part in the care we take in bringing you “Absolutely the Best Coffee in the World”.
But what exactly happens when we are roasting your coffee? Roasting coffee transforms the chemical & physical properties of green coffee into roasted coffee that keeps millions world wide moving everyday. Makes us sound pretty important, huh? From Wikipedia, “The roasting process is what produces the characteristic flavor of coffee by causing the green coffee beans to expand and to change in color, taste, smell, and density.” There are several complex chemical reactions that take place as coffee is being roasted, such as the Maillard which is a chemical reaction between amino acids and reducing sugars that gives browned foods their desirable flavor.
What equipment do we use when roasting your coffee? How do we do it? Roasting coffee is usually done in a drum roaster, a large rotating drum over a flame usually powered by natural gas. Wood can be used as well, but is much harder to keep the even temperatures needed for coffee roasting. There are also smaller coffee roasters that run on electricity, mostly for home use. Coffee should be roasted as close to when it will be consumed, packed or shipped in order to preserve freshness and taste. After we receive your order, we begin roasting your coffee when the roaster is warmed at three hundred fifty degrees. The green coffee hopper is loaded and as the empty drum is filled, the temperature will drop down to 200 degrees or so. The drum spins to evenly distribute heat to all the beans on all sides (since one side of the bean is flat). As the temperature of the beans increase, it is important to maintain the rate at which the coffee heats inside the drum. If it gets too hot too quick, the coffee will scorch, and leave you with a burnt taste in your cup. As the beans heat up, the flame needs to be controlled to maintain an even temperature as we are roasting your coffee. As the beans heat up, there is a burnt grassy smell that lets us know the roasting process is beginning and the beans will turn a tan color.
Next, is the first major step in the coffee roasting process, “The crack”. There are two temperature thresholds called “cracks” that we listen for. At about 382–396 °F, beans will emit a cracking sound much like popcorn does when it pops, only much quieter. This point is called “first crack,” marking the beginning of light roasts. The coffee will have an earthy, grassy taste at this point, however this is the point that the beans true flavor is pronounced, and most cuppers choose to cup coffee right after the first crack. As temperature rises, we closely watch temperature, color, and smell to determine the correct roast. This is where art meets science and is a skill that takes years of practice to get used to; a lot of trial, error and patience is involved. Most of our coffees will be roasted during this point in the roast. It is amazing to study the effects of how just a few more degrees or turns of the drum can give you a different taste all together as in the case of our Roasters Pick – Papua New Guinea-Chocolate Roast. We brought our usual roast up to medium/dark which lends less of the fruity notes, and more of a nutty, chocolaty taste. This is just one example of how we can differentiate coffee origins, roast profiles and tastes as we keep learning our craft of roasting your coffee.
We bring out the Chocolate notes of Papua New Guinea when we are roasting your coffee a few degrees more.
When the beans are at about 425–439 °F, they emit a “second crack.” During the second “crack” pressure inside the bean has increased to the point where the structure of the bean fractures, rapidly releasing gases, thus a second audible sound is emitted. At this point, depending on the bean, you will be at or above a medium roast as the second crack occurs, depending on the age of the bean, moisture conditions, amount of coffee being roasted and so on. This second crack is the beginning of the end of the bean’s time in the roaster, as oils will now begin to seep out of the cracks in the bean’s structure due to the heat and expansion as sugars inside heat up further. Beyond this point, and the oil will begin to burn on the outside of the bean, and will accelerate the bean’s burning if they are not removed from the drum. Some folks like their coffee at this stage, but it it usually a place for espresso/cappuccino style roasts, or people who enjoy a charred taste to their coffee.
We hope you learned a bit more about what goes on during the roasting process. Next week, we will discuss the different stages and names for different roast profiles.