From Green to Gourmet: How are Coffee Beans Roasted?

how are coffee beans roasted

From delicious frappuccinos to intense espresso shots, coffee has no shortage of popularity. Consumers are drawn to coffee mainly because of its stimulating effects. However, that’s not to say that the flavor and aroma aren’t persuasive, too – and it’s all thanks to the roasting process.

Roasting plays a significant role in the flavor and scent departments. Coffee beans are roasted in special roasting equipment for a specific period. How long the beans are roasted will determine the final taste and color, from light to dark.

Keep reading to learn more about how coffee beans are roasted. 

The Basics of Coffee Beans

Coffee beans are the seeds found inside the fruit from coffee plants. These fruits are known as “coffee cherries.”

There are two main types of coffee beans:

  • Arabica – Arabica beans are known for their incredible smoothness and deliciously sweet flavors that are mild yet may have fruity or nutty undertones. They’re the preferred option for most consumers. 
  • Robusta – Robusta coffee beans are certainly more “robust” than Arabica. They have a bolder flavor and a higher caffeine content, so they’re commonly used in espresso blends. 

Regardless of where the bean comes from, it goes through an intensive process before becoming that handy cup of Joe we consume every morning before work. Coffee does go beyond Arabica and Robusta, though. Our article about the “different types of coffee beans” give you all the detail.

Why Roast Coffee Beans?

There are three significant reasons why coffee beans should be roasted.

  • Enhancing flavors – Did you know coffee beans are initially green and tasteless? Well, it’s true – and nobody wants to sip on that while enjoying a coffee cake. That’s where roasting comes in. During roasting, coffee beans change color and undergo chemical reactions that cause flavor development. So, thank the roasters the next time you notice some nutty, floral, or chocolate undertones.
  • Developing aromas – For some coffee enthusiasts, it’s all about the scent. Again, the delightful aroma wouldn’t be possible without roasting. 
  • Caffeine content – While caffeine content will also be determined by how it’s brewed and how much coffee you use, roasting also plays a slight role. Contrary to popular belief, the caffeine level per coffee bean remains pretty stable throughout the roasting process. However, light roasts usually have slightly more caffeine by weight because they have not lost as much water compared to darker roasts. 

The Roasting Process Unveiled 

Roasting is a critical process for coffee beans. It’s what creates the delicious flavors and aromas hooked by 79% of the US population.

How does it all happen, though?

Here’s a quick breakdown of the roasting process.


The process starts with selecting the best green coffee beans to be roasted.

Pickers look at various factors, but moisture content is one of the biggest.

According to the International Coffee Organization (ICO), the ideal percentage is between 8% and 12.5%. That’s because too much moisture can lead to trouble while roasting, while too little moisture will create an undesirable flavor and smell.

The Roasting Stages

Once the perfect green coffee beans are selected, it’s time to move on to step two – roasting them. This can be broken down into five sections:

  • Drying stage – Green coffee beans are dried in a heated roasting machine (typically a drum roaster). This process usually takes around six to eight minutes. At the end, the beans will be approximately 320°F.
  • First crack – As the coffee beans lose moisture and grow, there will be an audible cracking sound. This typically occurs at 385°F and indicates that a lighter roast is beginning.
  • Development stage – The coffee beans develop their flavor and smell during this stage. The outcome will depend solely on the temperature and time of development.
  • Second crack – Some roasters will allow their coffee beans to crack once more. This is called the “second crack” and is best suited for darker roasts.
  • Cooling – When the coffee beans have reached their intended roast level, it’s essential to cool them immediately – within 4 to 5 minutes. This is crucial, as coffee beans will continue to roast, which can harm the flavor.

Different Levels of Roast

As most coffee aficionados know, there are different coffee roast levels on the market. However, if you’re new to the world of coffee drinking and aren’t sure which roast level is right for you, here’s a quick look at the different levels and their characteristics.

  • Light – The lightest option, light roast, is known for being subtle, lighter in body, and more acidic. It’s typically used in cold brew methods, pour-overs, and AeroPresses.
  • Medium – If you’re looking for a coffee with a bit more intensity, medium brew is an excellent choice. This roast can have a wide range of flavor undertones and can be used in many brewing methods, including French press, drip, and pour-overs.
  • Dark – The final option is the dark roast. As the name suggests, dark roasts have a bold and bitter flavor with less acidity. This is the roast most commonly used for espresso shots and drinks. 

Home Coffee Roasting

If you want complete control over your flavor profile and enjoy the freshest coffee of your existence, consider roasting coffee beans at home. Yes, you can roast coffee beans in the comfort of your kitchen; no, it’s not extremely difficult.

Here’s a quick look at how to roast coffee beans at home:

  • Purchase some green coffee beans. It’s best to buy a variety pack until you can find one you really enjoy. You’ll also need a piece of equipment for roasting. 
  • Purchase the right equipment. You can use your oven, but that can be complicated. Popcorn machines can work like a charm. The best option is to buy an at-home coffee roaster. (Some are surprisingly budget-friendly!)
  • Get roasting! The perk of going the coffee roaster route is that you can follow along with the directions. Most of the time, you’ll need to roast your beans for 10 to 20 minutes, depending on your desired outcome. Remember that the best temperature for coffee roasting is between 356°F to 482°F. Also, keep in mind that these are “general” guidelines and, depending on the bean, equipment, and roast you are looking for can vary.
  • Cool the beans. Once the time has been reached, remove the beans immediately and cool them down. The simplest way is to place a fan right next to the beans!

Here are a few tips for achieving the best coffee roast roast at home:

  • Start small – Getting it right on the first try is difficult, if not impossible. Start small until you know what you’re doing. Otherwise, you’ll waste a lot of those precious coffee beans.
  • Pay attention to the cracks – Remember that the first crack indicates a light roast. A second crack is needed for medium and dark roasts.
  • Let the beans de-gas  – Unfortunately, you shouldn’t dive into your beans for a fresh roast coffee immediately. Allow them to de-gas for at least 1-14 days. 
  • Store your roasted beans correctly – When all is said and done, it’s essential to store your coffee beans correctly. An airtight container is best. It’s recommended to add silica desiccants to absorb any excess moisture.

Famous Coffee Brands and their Signature Roasts

Are you curious about the signature roasts of your favorite coffee brands? I don’t blame you. That’s why I’ve done a little research to find out the signature roast and flavor profile of some of the top companies:

Coffee BrandSignature RoastRoast (Light, Medium, Dark)Flavor Profile
Death WishDark Roast CoffeeDarkDark Chocolate, Black Cherry
BonesHigh VoltageMediumStrong, Rich
Black RifleSpace BearLightCitrus Floral, Black Tea
StarbucksSignature EspressoDarkBold, Caramelly


Roasting is an essential part of every coffee bean’s journey. It’s responsible for the flavor and aroma, yet also plays a role in the caffeine content. The best part is that you can experiment with roasting to achieve a taste right for you! Also check out our article on how coffee beans are harvested to learn how these two topics go hand-in-hand.


How does roast level affect coffee flavor?

Roasting plays a crucial part in flavor development. During the development period, several chemical and physical changes occur, affecting the final flavor of the coffee beans.

Can I roast coffee beans at home without professional equipment?

You can roast coffee beans at home without professional equipment. However, using an at-home roaster is beneficial as it is easy to use and comes with handy instructions.

Are coffee beans roasted when you buy them?

Coffee beans are roasted when you buy them unless you purchase green coffee beans that have yet to be roasted.

Are coffee beans roasted with oil?

Coffee beans are not roasted with oil. However, some are flavored with oils afterward.

Can you drink coffee right after roasting?

Coffee beans should be allowed 1-14 days to degas carbon dioxide from the roasting process before consuming

What are the disadvantages of coffee roasting?

Coffee roasting has many benefits, the two main advantages being enhanced flavor and aroma.

Why does coffee need to rest after roasting?

Coffee beans need a chance to de-gas carbon dioxide after roasting.

Does roasting coffee destroy caffeine?

Lengthy roasting times can reduce the amount of caffeine in coffees. Lighter roasts tend to have the most.


79% of Americans drink 2+ cups of coffee per day, survey finds. News Direct. (n.d.).

Ed 1939/05 E – international coffee organization. (n.d.-b).

Christopher Mize

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