Experienced, savvy baristas know that coffee comes in many different forms and can be prepared in a wide variety of ways. Coffee is grown in abundance everywhere from Brazil (which is the world’s largest coffee producer), Colombia and Honduras to Ethiopia and Uganda to India, and it comes not in one particular flavor, but in many different flavors. Whether one enjoys coffee with a deep, rich, full-bodied flavor, a light flavor or a flavor that is somewhere in between depends a lot on the way in which coffee is prepared, and that preparation begins with the process known as roasting.
What is coffee roasting?
Coffee roasting is the process in which the coffee beans are heated in order to achieve solubility — that is, the ability to dissolve in water. Without the roasting process, green coffee seeds would not be able to dissolve in water and provide a great coffee taste. Coffee is typically roasted in a large commercial roaster, a cylindrical machine that turns over and over like a clothes dryer and has flames underneath. But a traditional roaster isn’t the only way to roast coffee, which can also be roasted using a cast iron pan or a popcorn popper.
Which coffee roast has the most caffeine in it?
Legend has it that because a darker coffee roast has a stronger, more intense flavor, it has the most caffeine. But that’s a myth. Truth be told, 50 grams of a darker roast and 50 grams of a lighter roast have roughly the same amount of caffeine. It is the density of the beans, not the coffee’s overall weight, that determines the amount of caffeine. Light-roast beans have a greater density than dark-roast beans; so, with a light roast, each individual bean has slightly more caffeine — whereas with a dark roast, each individual bean would have slightly less caffeine.
Coffee beans, in their unprocessed state before roasting, are green and have a grassy smell; it is after roasting that they turn a shade of brown and acquire the aroma one typically associates with coffee. The shade of brown is determined by the type of roast. With a light roast, the beans turn a light brown — and light roasts are typically achieved by roasting the beans at a temperature of 356-401°F/180-205°C. Light roasts are known for having a toasted grain taste and for their obvious acidity, and their light brown color remains after they are turned into liquid coffee.
With medium roasts, coffee beans are turned from their original green to a medium brown, and this type of roast requires a higher temperature than a light roast — typically, somewhere between 410-428°F or 210-220°C. Medium roasts lack the toasted grain taste associated with light roasts, and they have more body. But like light roasts, medium roasts have no oil on the surface of the beans. Medium roasts are known for having a more balanced aroma, flavor, and acidity than light roasts, and they have slightly more caffeine than light roasts. That medium brown color remains after the roasted beans are ground up.
When green coffee beans are given a medium-dark roast during the roasting process, they acquire a brown color that is darker than medium roasts and much darker than light roasts yet not as dark as a dark roast. A medium-dark roast typically requires temperatures of 437-450°F/225-232°C, and this type of roast gives coffee a flavor that has more body than a medium roast or a light roast. And with a medium-dark roast, one begins to see some oil appearing on the beans — although less oil than with a dark roast.
The roasting process turns all coffee beans from their original green to some shade of brown, and with a dark roast, the beans are turned to a very dark brown that is almost black in its appearance. A dark roast requires temperatures of 465-480°F/240-248°C, resulting in beans that have a great deal of body and have a deep, rich, smoky, somewhat bitter taste. With a dark roast, beans become thinner — and with decreased density, there is slightly less density in each coffee bean. With a dark roast, one sees more oil on the surface of the coffee bean.
With the coffee roasting process, there is not a “one size fits all” approach or a “correct” approach. Some coffee lovers prefer the light brown texture and the toasted grain taste of a light roast, while other coffee lovers crave the deep, full-bodied smokiness of a dark roast — and medium and medium-dark roast options are somewhere in between. Some coffee enthusiasts enjoy all of the different roasts, depending on what they are in the mood for on a given day. There are no cardinal rules when it comes to choosing a type of roast — and with coffee, different strokes please different folks.