Your Guide to Coffee Roasting

Roasting coffee beans is a lot like roasting a turkey for Thanksgiving. When done correctly, roasting helps your meal taste better and brings out the richness of your ingredients. However, if you rush the roasting process or let it roast for too long, your ingredients can be inedible or burnt. 

Roasts are key to making the perfect cup of coffee, so here is a quick guide to roasting techniques and how they can affect your final brew. 

Does Coffee Have to Be Roasted?

If you want your coffee to taste like coffee, your beans must be roasted. 

While it is possible to technically make coffee from green (unroasted) beans, it will taste disgusting. The traditional aroma will be missing, and the taste will be bitter and astringent. 

What Happens During Roasting?

The three key phases to roasting are the drying, caramelization, and the first crack phases. Each phase helps unlock the potential flavor of the green bean and can drastically affect the final brew. 

Drying Phase 

Green beans are internally wet. They hold a lot of moisture and need to be completely dried out before they can be effectively roasted. During this phase, the bean changes from green to yellow in color, and through evaporation, it loses a significant amount of mass and density. 

For most roasts, this initial drying phase takes up to 40% of the roasting time. 

Caramelization Phase

Once beans turn yellow, they start to caramelize. During this time, the internal heat creates chemical reactions that eliminate the astringent taste of green beans and develop the aroma and distinct taste of a perfectly brewed cup of coffee. 

It is during this phase that the Maillard reaction happens. This is the most essential reaction in the roasting process between amino acids that reduces some of the natural sugars within the bean and causes the coffee beans to brown. This reaction is where coffee gains its flavor and aromatic compounds, so getting the most out of this stage is essential. When managed correctly and not rushed through, the Maillard reactions help coffee caramelize the natural sugars in the bean, creating a rich, floral, and chocolatey taste. 

First Crack and Development

Up to this point, the coffee bean has maintained its natural shape, but it will crack near the end of the caramelization phase, similar to how a popcorn kernel pops. The internal pressure generated by the roasting process becomes too strong, and the bean splits open. This phase is critical because it determines the final flavor of your coffee and whether the roast is light or dark.

As a rough rule of thumb, a shorter development phase leads to a light roast, which creates a tart and fruity coffee. A more prolonged development phase creates a dark roast, which has lower acidity and richer, earthier, caramelized flavors. 

How Long Should I Roast My Coffee Beans? 

We wish we could give you a formula for the perfect roast, but there are too many variables to give a generic solution. Here are some items to consider when finding the best recipe for your taste.

The optimal roast time for coffee beans typically falls between 8 to 16 minutes, depending on your desired roast level, batch size, and roasting setup.

Here’s a general guideline:

• Smaller batches (like 1/2 lb or less): 5–8 minutes
  
• Standard 1 lb batches: 14–16 minutes is common
  
• Lighter roasts: Often completed in the 8–11 minute range
  
• Darker roasts: May stretch toward 14–16 minutes
  

Other Important Considerations:

• Taste is key — There's no strict time that defines a "good" roast. If the coffee tastes good to you, that's a success.
  
• Roast Development: Avoid "baked" coffee, which can happen when a roast is extended too long without enough development (usually over 16+ minutes depending on the profile). Baked beans tend to lose acidity and complexity, much like an overcooked steak.
  
• Roasting Curve Matters: Pay attention to your Rate of Rise (RoR) and ensure it's declining smoothly during the roast. Sudden dips or spikes can affect taste more than total roast time.
  
• Experimentation Helps: Try roasting intentionally longer or shorter to taste the difference. Feedback from your own palate is the best guide.
  

Ultimately, there’s no perfect number — use your taste buds, roast curves, and personal preferences to dial in the sweet spot.

What Are the Different Types of Roasting? 

There are two methods of roasting coffee - drum roasting and hot air roasting. Drum roasting provides more complex flavors but takes longer, while hot air roasting is more accessible and provides a faster roast, but it comes at the cost of the final flavor profile.

Drum Roasting

Drum roasting is the more traditional method of roasting coffee. Green coffee beans are placed in a metal drum and heated. Metal arms stir the beans as they rotate to ensure an even roast.

Drum roasting is a gentle process in which the beans are roasted at a lower temperature for longer. This helps them stay in the caramelization phase longer, creating more complex flavors and a stronger aromatic profile.

If you want to simulate drum roasting in your kitchen, you can use a saute pan on medium heat and stir the coffee beans with a wooden spoon. Once the beans have all achieved their first split, remove them from the pan and cool in a well-ventilated location. Remember that roasting is a slow process that requires patience.

Hot Air Roasting

Hot air roasting involves exposing coffee to hot air. Like a standing popcorn machine, a hot air roaster uses convection to control the roast. It provides precise control over the temperature, creating a more uniform roast that is faster. However, this means some potentially complex flavors are never achieved, usually resulting in a more bitter and acidic roast. 

If you want to try hot air roasting at home, look for a roaster that allows you to control the time and heat of the roast. This will give you the most control of the roast, ensuring you get the flavor profile and roast you want without risking over-roasting or scorching. 

Enjoy the Perfect Roast Every Day

Coffee is a journey that can be tasted in every sip. Visit our store today and get the tools and beans you need to enjoy your best coffee daily.