Commercial coffee roasting machines are used to heat the green coffee beans between 370 and 540 degrees Fahrenheit. They’re heated anywhere from a few minutes to half an hour. The time and temperature determine the level of roast from light to dark.
Roasting Levels
A majority of coffee drinkers have a range of preferences when it comes to the coffee’s roast. Whether the drinker desires a lighter or darker roast, a favorite is always just a sip away.
It should be noted that a dark roasted coffee does not necessarily mean it contains higher caffeine content. On the contrary, lighter roasted coffee tends to have slightly higher caffeine quantities than medium to dark roasts. This is due to the roasting techniques utilized that directly impact the flavor profiles and caffeine levels.
Light Roast
Light roasted coffee beans are light brown in appearance. They also express lighter, more acidic flavor profiles. To achieve a lighter roast, the bean is heated until the “first crack” at about 375 – 400 degrees Fahrenheit. The appearance of the beans is not shiny or oily. That is only developed when a bean is roasted longer releasing the oils it contains. Lightly roasted beans also express greater origin flavors that exist from the parent soil it was grown in. Additionally, concurrent weather conditions and location next to other crops will directly affect its flavor profile.
Medium Roast
Medium roasted coffee has a slightly dark-tan/brown appearance. Medium roasted beans provide for a sweeter, more balanced profile with less acidity than darker roasts. Caffeine levels are less than light roasted but higher than the dark roasted varieties. Medium roasts are met at temperatures between 410-430 degrees Fahrenheit. This occurs between the first and “second crack.” A shiny appearance will be really subtle as some oils are released during this process.
Dark Roast
Dark roasting will allow the coffee bean to release most of its contained oils, giving it an shiny appearance with a less acidic taste. Dark roasted coffee beans are processed around 460 degrees Fahrenheit near the end of the “second crack.” Flavor profiles will be slightly bitter or smoky from the length and heat in this roasting process. The dark roasted flavors may overwhelm the origin/source flavors of the coffee.