Roasting Coffee

How do coffee beans develop their aroma and flavors? Roasting is the key to unlocking the hidden features of coffee beans. When roasting, there are chemical changes that happen as the beans are rapidly exposed to very high temperatures, and when they reach the peak of perfection, the beans are quickly cooled down to stop the process. 

 

As a result, the beans are now brown or darker depending on the type of roast, and it weighs less now because the moisture has been drawn out, and it is now what we call coffee beans ready to grind and brew. Roasting forges 800 to 1000 varieties of aroma compounds that make the flavor of the coffee but before we talk about how roasting affects aromas and flavors, let's have a brief discussion about the stages of roasting.

 

Drying Phase

Drying is a necessary stage because the beans that were processed and dried in origin are not entirely dried, so there's still about 8-12% moisture left in the bean to preserve its quality. This stage usually takes about 4-8 minutes and typically ends at around 320°F. At this point, the beans increase in bean volume and internal pressure while losing the beans mass and density as well as it changes to accentuated yellow. It is crucial in this stage not to start with too much heat and not dry too fast as it will result in an uneven distribution of heat. Take note that the timing and temperatures are normally based on the characteristics of the coffees.

 

 

Maillard Phase

This is also called the "Browning Stage." During this stage, the sugars and amino acids are reduced and broken down, creating several different aromas and brown-colored compounds called melanoidins and developing the acidity of the coffee. At this point, the roasting slows down to ensure flavor development.

 

Development

During this stage, the "first crack" happens between 6-7 minutes which sounds similar to a popcorn cracking and which also means the beans begin development. It also continues to slow down the roasting process to develop the selected aroma compounds and the flavor. For Light Roasts, the development end right after the first crack. For Medium Roasts, it takes a little longer before the "second crack," while for the Dark Roasts, it goes after the "second crack."

 

Cooling

This is the last step that takes place in a cooling tank. It is essential to bring the coffee beans to room temperature as soon as possible so they won't continue roasting and developing bitterness. It might end up "scorched beans" or, in other words, overroasted beans. The grading process also happens in this stage wherein defected roasted beans are removed, such as under roasted beans and overroasted beans.

 

Coffee Roasting Spectrum

This is a quick guide of the roasting spectrum

1. Green / Unroasted Coffee Bean

• Raw, sweet & fruity

2. Start to Pale

• About 275°F, Pale Green

3. Early Yellow Stage

• About 330°F, Pale Yellow

4. Yellow-Tan Stage

• 345°F, Golden

5. Light Brown Stage

• 370°F, Shedding Off the Chaff

6. Brown Stage

• Sugar and Amino Acids Breaking Down, Malliard Stage

7. 1st Crack Begin

• Bean Increase Volume Size

8. Middle of 1st Crack

• The Internal Temperature of the Beans is climbing to 370°F

9. 1st Crack Finishes

• Beans reach "City Roast", Considered as Coffee Already.

10. City + Roast

• Dark Brown

11. Full City Roast

• Almost 2nd Crack

12. Full + City Roast

• 2nd crack Begins, Lighter than Dark Chocolate

13. Vienna - Light French Roast

• Origin Flavor is taken over by roasting characteristics

14. Full French Roast

• Smoky, Dark Caramel, and Burnt Flavors
• Can Never Go Beyond This

15. Fully Carbonized

• Beans are now charcoal

 

Unique Flavor Profiles of Asia, Africa, and South America

There are three primary coffee growing and exporting continents throughout the world. They are in this area called the "Bean Belt," which is also mentioned as the area between The Tropic of Cancer and The Tropic of Capricorn. These continents are South America, Africa, and Southeast Asia and they all sit in the equator.

 

They produce the best coffee beans because they are grown at high altitudes, tropical climate, with very rich soil and the temperature is at about 70°F which is the perfect environment for Arabica coffee beans to flourish.

 

Flavor Profiles of Each Continent

South America

Colombia and Brazil dominate this continent. Both of them are the large producers of coffee in this location. Of course, Guatemala, Mexico, Panama, and Costa Rica also play a big part here. When it comes to the characteristics of their coffees, they have medium-bodied, medium acidity, balanced, sweet, nutty, and aromatic. In Brazil, they have medium to full-bodied, nutty, chocolatey, and buttery coffees. But Brazil also has clean, fruity, and high acidity coffees. This continent is famous for having well-balanced, nutty, chocolatey, and has smooth finish coffees.

 

Africa

Africa is where coffee originated, specifically in Ethiopia. Both Kenya and Ethiopia are famous when it comes to sweet, fruity, and exotic coffees. They have high acidity notes, floral aroma, and fruity flavors, making them full-bodied and full-flavored coffees. Kenya is also is famous for its winey flavor, clean acidity, and full-bodied, full-flavored coffees.

 

Southeast Asia

Indonesia and Vietnam are the two most popular countries that produce diverse characteristics of coffees in Asia. The signature flavor profiles in this area are dark, rich, earthy, low acidity, and full-bodied coffees that will be heavy on your palette. Though Vietnam mainly offers Robusta beans, other places like Papua New Guinea, the Philippines, and Indonesia produce mostly Arabica beans. This continent is popular with its rich and earthy characteristics that suit heavy coffee lovers.

 

It's wonderful to have this variety of flavors and characteristics for every coffee drinker to find and discover what can satisfy and give their palette an amazing experience from each of this unique continent's flavor profiles.

For an additional visual reference, here's a downloadable infographic of this article.

 

Want to learn one of the most popular ways to brew an excellent cup of coffee? In this brief article, we'll talk about how you can get started in pour-over and Why Pour-Over Method?