Answering 5 Common Questions About Coffee Roasting

At Terminal 3, our mission is to extend our passion for specialty coffee by educating people about the craftsmanship that goes into your morning cup of coffee.

Frequent visitors to our store know that one of the unique experiences we offer is the opportunity to watch our roasters in action as they roast our carefully handpicked beans on-site. Getting a close look at this typically behind-the-scenes roasting process often gets our customers curious, sparking a greater interest for the journey from bean to cup.

In this release of the Gateway article, we address five frequently asked questions about roasting that we often get from our visitors to give you a deeper understanding of the process and how it impacts the coffee you love.

What happened to the beans during the roasting process?

During the roasting process, green coffee beans are heated at high temperatures, causing significant physical and chemical changes.  Initially, the beans turn yellow and start to emit a grassy aroma. As the temperature rises, the beans undergo a Maillard reaction, where natural sugars and amino acids react, producing complex flavour and a brown colour. The beans then enter the first crack stage, where they expand and release steam, resembling the sound of popcorn popping. This is a critical point as it marks the transformation of the beans into a roasted state, developing the desired flavour and aroma. The roasting process continues until the desired roast level is achieved – whether it is light, medium, or dark roast.

How does roast level affect coffee’s flavour?

Roasting offers greater flexibility and control for us to customize the flavour and strength of coffee beans to deliver the optimal taste experience to our customers. The roast level plays a crucial role in determining the flavour profile of the coffee. Light roasts preserve more of the beans' original characteristics, resulting in a brighter acidity and a lighter body. They often highlight fruity and floral notes. Medium roasts balance the beans' unique flavour with roast characteristics, producing a well-rounded flavour with a medium body. Dark roasts, on the other hand, emphasize the roasting process itself, creating bold, robust flavour with lower acidity and a fuller body. These roasts often have chocolatey, nutty, or smoky notes. Each roast level offers a unique taste experience, catering to different preferences.

How do you determine the roast profile for different coffee beans?

Determining the roast profile for different coffee beans is both an art and a science. We start by understanding the origin, variety, and processing method of the beans, as these factors influence their inherent flavour. Through careful experimentation, we roast small test batches, adjusting variables like temperature, time, and airflow. We taste each batch – a process known as cupping – to evaluate the flavour and make adjustments until we find the optimal roast profile that enhances the beans' unique characteristics. This process ensures that each batch of coffee delivers a consistent and exceptional flavour.

How long does it take to roast a batch of coffee beans?

The time it takes to roast a batch of coffee beans varies depending on the size of the roaster, the desired roast level and the specific characteristics of the beans. On average, roasting a batch typically takes between 9 to 14 minutes. Light roasts usually require a shorter roasting time, while dark roasts take longer to achieve their deep, bold flavours. Throughout the process, our roasters carefully monitor the beans, making real-time adjustments to ensure precise control over the final product.

Can you brew coffee beans immediately after roasting?

Many people believe that fresher is always better, but this isn’t the case with coffee beans. While it's technically possible to brew coffee beans immediately after roasting, we recommend waiting at least 24 hours for the beans to degas. During roasting, gases such as carbon dioxide are trapped inside the beans. Allowing the beans to rest after roasting gives these gases time to escape, which helps improve the extraction process during brewing. This resting period, also known as degassing, typically takes anywhere from one to three days. Freshly roasted beans that have been allowed to degas will produce a more balanced and flavourful cup of coffee.

Check out our article: Do I Need to Rest Coffee Beans After Roasting?

We hope these insights can give you a better understanding of the process that goes into your cup of coffee. Thank you for being a part of our coffee journey.