The coffee roasting process
The roasting process is what produces the characteristics flavor of your coffee by causing the green coffee beans to change in taste. successful roasting is difficult because freshly roasted beans quickly lost the volatile oils that give coffee flavor and aroma. So, Before we learn how to roast our own coffee at home, let’s take a general look to find out how the professional coffee roasting Process works. Because it’s essential to know how is coffee proceeds and roasted before you make your own. As you will discover it is the same process with different tools.
In the roasting process, heat from an external source is applied to the raw coffee beans in large vats or drums, spinning and heating them evenly at temperatures reaching up to 550°F (290°C). The heat essentially creates chemical changes in the physical structure and composition of the beans.
Water evaporates from the beans, starches convert to sugars, and the sugars caramelize. The beans increase in size by 25 to 35 percent. They begin to pop, much like popcorn. They lose 18 to 22 percent of their weight, mostly through this evaporation. The caffeine content, however, is not affected by these changes. Gradually, the green beans turn a yellowish color, then darken to a deep rich brown.
During this color change, a number of chemical reactions occur, causing the beans’ sugars and proteins to interact with each other. It is these changes, and the release of coffee oil, that are essential in bringing out the flavor and aroma of the beans. The darker the beans, the more oil they produce. Great care must be taken as the process nears completion, to ensure that the beans are not burnt.
Flavorful acids form as the beans turn into a medium-dark roast. As the roasting progresses toward a darker roast, these same acids will now begin to break down, and the sugar components will start to caramelize. A darker roast has more body and an intense richer flavor to the palate. That is why espresso beans are characteristically low in acidity, rich in body, and sometimes caramel-like (caramel, after all, is just roasted sugar).
After this monitored roasting process, the coffee beans are rapidly cooled down by jets of cold air, thereby sealing in all the flavor and aroma that the heated air has brought to life from the dormant green beans.
The lighter the roast, the more flavor acids, resulting in interesting flavors and sparkle. Lighter roasts are lighter in the body because the roast has not produced caramelized sugars or coffee oil.
Medium roasts have less acidic snap; they are richer, with a more rounded flavor. Here, coffee oils begin to appear. At the dark roast stage, all acidic tones disappear; the beans are oilier; there is a definite bittersweet, chocolatey flavor; the brew is rich and full in body and texture.
An interesting note on roasting as it pertains to caffeine content: The darker the roast, the less caffeine content it will have. Higher, longer roasting temperatures eliminate more caffeine from the beans than will a brief, cooler roast. Before we learn how to roast our own coffee at home, let’s take a general look at how the professional coffee roasting Process works. Because it’s essential to know how is coffee proceeds and roasted before you make your own. As you will discover it is the same process with different tools.
how to Roast Your Own Coffee at Home
All over the world, many coffee aficionados roast their own coffee, to enjoy the satisfaction of the ritual and the freshest cup of coffee possible. For those concerned about the environment, home roasting is ideal. A big sack of raw green coffee beans is certainly more economical than buying commercially roasted brands: home-roasting can curb the processing, packaging, and advertising expenses of purchasing small cans or bags of coffee at retail prices.
Nowadays, there are very good electric home-roasting machines, but for “back-to-basics” roasting, simply use a skillet on the stovetop or in the oven. The physical procedures of these latter methods are also simple: first, the raw green coffee beans need to be kept moving in temperatures of at least 400°F (200°C) and, second, they have to be cooled down at the precise moment of the desired degree of roast.
Method N° 1: The Skillet-On-The-Stove Method
one of the best methods on how to roast your own coffee at home is by Using an old, heavy metal skillet (with a handle and cover, and without a nonstick coating), spread only one layer of green coffee beans in the pan at a time. (An aluminum egg poacher pan works nicely).
Place an inexpensive oven thermometer in the pan. (Ideally, it should have a flat metal back that can be stood at an angle in the pan. It can then register the temperature of the air in the pan rather than the temperature of the bottom surface of the pan.)
During the roasting process, smoke will start to seep out of the pan when the beans begin to pop, so make sure the windows are open, your smoke alarm is turned off, and the kitchen’s air ventilator is on.
Begin with medium heat and raise the heat until the thermometer registers 500°F (260°C). Then decrease the heat to a steady 400°F (200°C). Peek at the thermometer once in a while to be certain that 400°F (200°C) is being maintained.
Holding down the cover on the pan, begin to gently shake the pan at 1-minute intervals, to roast the beans evenly. Anyone who has made stovetop popcorn will recognize this is the same technique. The beans will begin to snap, crackle, and pop! The beans will begin to change color, first becoming a yellowish-brown, then swelling and darkening. Take a peek and watch the color, and stop roasting just before the desired color has been achieved (the beans will retain their heat and continue to darken for a moment or two longer).
It is important to never let the beans darken to more than a chocolate brown color, or else they will taste burnt. Once the desired roasting has been reached, immediately remove the pan from the heat and dump the beans into another cool pan or onto slate or marble. The quick cooldown will close the bean pores to preserve the coffee’s aroma, and halt the roasting process.
Method N° 2: The Skillet-In-The-Oven Method
Preheat the oven to 500°F (260°C). Spread an even layer of green coffee beans (1/2 inch/1.3 cm) in an old cast-iron skillet and place in the preheated oven. Roast for 20 minutes. Shake the pan occasionally during the roasting time, for a mild to medium roast. The green beans will first turn yellow, then brown. The beans’ natural moisture will begin to steam off.
A “first crack” will be heard as the remaining moisture bursts from the beans and releases the coffee’s rich aroma. For a darker roast, reduce the heat to 400°F (200°C) after 20 minutes, and continue to roast, stirring occasionally, for another 20 minutes (maximum) or less, depending on what degree of darkness you desire.
Once the desired roasting has been achieved, remove the pan from the heat to cool the beans.
A Note On Using Stovetop Popcorn Poppers
These neat stovetop pans can double as coffee roasters. Many kitchen boutiques sell them, retailing from $15 to $30. Follow the stovetop coffee-roasting directions. You will need to insert an oven thermometer to establish the proper temperature (as noted above) before the beans are shaken around in the pan.