By Ted Chan, Managing Editor of Coffee Roast
Roasting coffee is both a science and an art where green coffee beans are heated until their internal temperature reaches the desired level. The degree to which coffee beans are roasted dramatically affects their flavor. For a better understanding, let's look at the nine categories of coffee roast classification that we use. We'll focus on the roasting temperature, flavor profiles, and visual characteristics.
Blonde roast, known as cinnamon roast due to its color, is one of the lightest roasts available. Technically, these beans are roasted until they reach an internal temperature of around 196°C-205°C (385°F-401°F).
Visually, blonde roast beans are light brown and dry without any oil on the surface. This is because the roasting process has yet to cause the oils in the bean to break through to the surface. Just because the internal temperature is low doesn't mean the beans haven't been "cooked". Think of roast or egg that's cooked for longer at a lower temperature. A roaster's discretion with blonde roasts can create many interesting characteristics.
Flavor-wise, blonde roasts are often described as having a light, delicate flavor with a sweet and slightly tangy brightness. In addition, they often exhibit the most pronounced acidity and retain the most caffeine.
Light roasts are heated until an internal temperature of around 205°C-212°C (401°F-414°F). They're also known as half city or New England Roast.
The beans are a medium-light brown, still dry, with no oils on the bean surface. The roast is stopped shortly after the first "crack"—a popping sound signaling moisture released from the beans. Specialty coffee is often light roasted to preserve and accentuate the unique flavors and characteristics inherent in the high-quality beans, allowing the complex and delicate flavors to shine through in the final cup.
Light roast coffees tend to have a toasted grain, black tea, or brown sugar character with pronounced fruitiness and acidity. They exhibit more of the original flavor of the coffee beans, including their unique characteristics influenced by their growth conditions.
Light-medium roasts, often referred to as the American roast, reach an internal temperature of approximately 219°C-225°C (426°F-437°F).
The beans take on a medium brown color and may show a slight sheen from oil, indicative of the roast reaching the end of the first crack.
Light-medium roasts offer a balanced flavor, aroma, and acidity. They maintain some of the coffee's original flavors, combined with the flavor of the roasting process, creating a more complex taste profile.
A medium roast, commonly called a city roast, is roasted to an internal temperature of approximately 225°C-230°C (437°F-446°F).
The beans are a rich brown color and might start to show some oil on their surface.
Medium roast coffees often exhibit a fuller body and richer flavor while preserving some of the coffee's original flavor characteristics. The balance between acidity and body is well maintained in medium roasts.
Vienna roasts are a shade darker than medium roasts and are brought to an internal temperature of approximately 230°C-235°C (446°F-455°F).
The beans have a moderately dark brown color with a noticeable oily surface, signaling the beginning of the second crack during the roasting process.
Vienna roast coffee has a slight hint of dark chocolate or caramel, with a reduced acidity compared to lighter roasts. They also have a slightly smoky aftertaste due to the longer roasting time.
Medium-dark roasts, or full-city roasts, reach an internal temperature of approximately 235°C-240°C (455°F-464°F). The beans appear somewhat dark, and the surface is oily. The roast is typically stopped midway through the second crack.
Flavor-wise, medium-dark roasts have a heavier body than the lighter roasts, with a balanced blend of the roast's flavor and the original taste of the beans. There are often spicy or chocolatey notes with moderate acidity.
Dark roast works as a bit of a catch-all category on Coffee Roast since so many roasters specify a roast of dark but this can mean a roast anwhere from 230°C-245°C. Visually, the beans are dark brown and may have a shiny, oily surface. The coffee beans have usually undergone or reached the second crack at this stage.
Dark roast coffees are characterized by their bold, rich, and robust flavor. The roasting process overpowers most of the original flavors of the beans and imparts a distinctly smoky or slightly burnt taste. The acidity is low, while the body of the coffee is often full and robust.
Dark roast, also known as French roast, has an internal temperature of around 240°C-245°C (464°F-473°F). Visually, the beans have a dark brown color and a shiny, oily surface. The coffee beans have clearly undergone the second crack at this stage.
Dark roast coffees are characterized by their bold, rich, and robust flavor.
The roasting process overpowers most of the original flavors of the beans, and imparts a distinctly smoky or slightly burnt taste. The acidity is low, while the body of the coffee is often full and strong.
Italian roast is one of the darkest roasts and is roasted to an internal temperature of 245°C-250°C (473°F-482°F). The beans are very dark brown, almost black, with a glossy, oily surface. This roast level is achieved after the second crack.
Italian roast coffee has a bold, full body and intense flavor with a slightly sweet aftertaste, often described as bittersweet. The acidity is almost non-existent, and the flavor of the roast significantly overpowers the beans' original flavor.