Coffee gets its aroma and flavors from the roasting process. The length of the roasting process can also affect the caffeine level in a bean, the body of the coffee, the acidity of the coffee, and sometimes the intensity of the flavor.
Light roasts are roasted for the least amount of time. Light roasted beans generally reach an internal temperature of 356°F – 401°F, right after the first crack occurs. These beans tend to not have the oils on them because they haven’t been roasted at a high enough temperature.
The longer a bean is roasted the more the heat pulls out the caffeine and the acidity. This means light roasts have the most caffeine and the most acidity. Light roasts can have a different taste profile, because the shortened roasting process prevents some chemical changes from occurring inside the bean. Origin flavors of the bean are more recognizable in light roasts, since the flavors that come from the roasting process often aren’t prominent. The acidity in light roasts is often accompanied by a citrus or lemon tone which some people find pleasing to the palate.
Medium roasted coffee reaches internal temperatures of 410°F-428°F. This is after the first crack and just before the second one occurs. They have a little bit more body than a light roast and less acidity.
Medium roasts are what the average American coffee drinker is used to. These roasts are considered to have balanced flavors. The acidity and body of a medium roast can vary, but are usually somewhere in the middle. Some examples of medium roasts are House blend, Breakfast roast, and American Roast.
Beans roasted to medium-dark reach an internal temperature of 437°F – 446°F. This is during or just after the second crack. This roast will also start showing the oils on the beans’ surface because the temperatures are high enough.
These roasts have a richer, fuller flavor, more body, and less acidity. Vienna Roast and Full-City Roast are some examples of a medium-dark roast coffee blend.
The roasting temperature for a dark roast is between 464°F – 482°F. There are visible oils on dark roast beans. Typically you cannot taste any origin flavors in a dark roast, just the affects the roasting process has on that type of coffee bean.
Dark roasts have sweeter flavors, because the sugars in the coffee beans have time to caramelize. The longer roasting process helps it to develop a richer flavor and full body, which often leads to it having a buttery finish. They also have the least acidity of all coffee roasts. Dark roasts have the least amount of caffeine because they’re roasted the longest. French roast is considered the darkest roast and has a pronounced smoky flavor. If coffee beans are roasted longer than a French roast (482°F), the oils and sugars in the bean will burn. Dark roasts often have European names because of the popularity of dark roasts in Europe, such as Italian roast.
Before coffee beans are roasted they are green and have almost no aroma, except for a natural earthy smell. The roasting process is what makes coffee beans into the delicious cup of coffee you’re drinking.
During the roasting process, coffee beans absorb heat which darkens their color. At higher temperatures, oils appear on the surface of the beans. At 401°F, the beans crack for the first time and start to expand. Around 437°F, they crack a second time. Coffee beans are never roasted above 482°F. Beyond that temperature, they will start to thin out and get a burnt taste.
Roast names and descriptions are not universal in the coffee industry. Going by the darkness of the color, however, is a common way to characterize the roast level of coffee beans. For this article, we are discussing light, medium, medium-dark, and dark roasts.
Now you know the roasting process and what changes it has on the beans at different roasting levels. If you’ve only ever tried an average medium roast coffee, try another roast. You’ll be surprised at the differences you’ll taste.
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