We all know the smell. Whether stepping into a coffee shop, opening up a bag of coffee at home, or sitting in front of a freshly brewed cup,
the aroma we all know and love is thanks to the final step in the coffee bean journey; the roast. Roasting coffee is a necessary step to turn
the processed green coffee beans into the fragrant, flavorful beans ready to be used in our favorite drink.
Roasting is a meticulous process and a difficult one to master. Getting the desired level and even roast usually requires the use of expensive
commercial roasters, which can closely monitor and adjust temperature and airflow. Different roast levels have different characteristics, and the
desired level can be dictated by the type of bean, and which flavors the roaster wants to highlight and showcase.
Because there are many names given to different roast levels, SCAA
(Specialty Coffee Association of America) has attempted to standardize the roast index by an Agtron number. The Agtron number refers explicitly to an
infrared reflectance measurement of a roasted coffee sample, specifically targeting the caramelization of sucrose. The higher the Agtron number,
the lighter the roast. Though the infared band used by Agtron
is outside the visible spectrum for humans, and doesn't reflect how we would perceive the coffee, in general lighter pale brown hues indicate light
roast, with dark, deep, shiny brown indicating a heavy roast.
Around the world, a country or regions favored roast level can demonstrate the flavor profile they value, as well as the style and types of
coffee drinks they enjoy.
Light Roast
Light roasted coffee is for those who enjoy fruity, floral flavors and higher acidity in their cup. More often seen in specialty and higher end coffee, light roasting keeps more of the beans inherent flavors, and showcases the variety, processing, and terroir of the bean more than other roast styles. Pale brown and a matte exterior are the visible signs of a light roast, with slightly fruity, floral, nutty, cereal like aromas permeating from the beans. Light roasts usually favor pour-over and drip style preparations, which bring out its delicate and nuanced flavors. Nordic coffee is known for being lightly roasted, and influencing the increase in lighter style roasts in specialty coffee.
Medium Roast
Sometimes called "American Roast" or "City Roast", medium roasted coffee brings richer, fuller flavors with more body and less acidity than light roast. Notes such as caramel, chocolate and nuts begin to develop as the cooking continues, as well as rounder fruit flavors (plum, peach etc.) rather than zesty, and diminished floral notes. Medium roasted coffee is generally good for drip and pour-over, as well as some espresso if a lighter, fruiter shot is the goal. A medium roast allows for the some of the beans inherent uniqueness and flavors to still come through, while giving it deeper and richer flavors from the roasting process.
Medium-Dark Roast
Rich and dark colored, medium-dark roast brings more depth and bitterness to the medium roast. As the beans continue to cook, the oil inside starts to break through the surface, which starts to give medium-dark roasts a glossy look. More richness and chocolatey notes come through, as well as a bittersweet aftertaste, while losing its fruitiness and acidity. The terroir and uniqueness of the bean is much less present at this stage, as the flavors from the roasting process begin to dominate the overall profile.
Dark Roast
Dark, shiny, and oily looking, dark roasts bring bold, deep flavors of bittersweet chocolate, dark caramel, roasted nuts with some bitterness. These coffees exhibit the least amount of acidity, and the fruity and floral flavors have all but disappeared and given way to the roasting process. There are many names for dark roasts: Vienna, French, Italian etc. which are staples in their region, and all have slightly different roasting levels. Dark roasted coffee is well suited for espresso style preparations and to be mixed with milk or cream, as the dark, bold flavors stand up well to mixing and softening.
Souces & References
- The Ultimate Guide to Understanding Coffee Roast Levels, https://coffeebros.com/blogs/coffee/the-ultimate-guide-to-understanding-coffee-roast-levels?srsltid=AfmBOoq77qYk9sSZDCgW-bW5DgDWogammFSXp_cDJB8ZVaeco63Ira4_
- Color measurement and ingredient quality - consistency control in coffee products – Measure Agtron Number and do more with Sensegood spectrophotometer, https://sensegoodinstruments.com/color-measurement-coffee-agtron-number.php
- Woodburn-Simmonds, M. (2023) Coffee Roast Guide, https://www.ncausa.org/About-Coffee/Coffee-Roasts-Guide
- Meister, E. (2023) A Simplified Guide to Roast Level, https://www.drinktrade.com/blogs/education/roast-level-guide?srsltid=AfmBOoq_1BXKRS2qajeMD6F4OlrINnBYXfuglJC_I_o1E0jOrFqZNs5t
- Roast Profile & Degrees of Roast, https://beans.at/en/kaffeewissen/kaffeeroestung/roestgrad-und-roestprofil