How to Roast Coffee and What It Means for Your Cup

If you love coffee, you might have wondered how it goes from green beans to the aromatic and flavorful drink you enjoy daily. The answer is roasting, a process that transforms the raw beans into roasted ones that you can grind and brew.

Roasting is an art and a science, affecting many aspects of your coffee's taste, aroma, body, and acidity. In this blog post, we will explain roasting coffee, how it works, and the different coffee roast types.

What is roasting coffee?

Roasting coffee applies heat to green coffee beans to develop their flavor, color, and aroma. Green coffee beans are the seeds of the coffee plant, which are harvested, processed, and dried before they are ready for roasting. Green coffee beans have a grassy and earthy flavor and are hard and dense. They also contain much moisture, which needs to be reduced during roasting.

Roasting coffee involves heating the beans to high temperatures, usually between 350°F and 500°F, for a certain amount of time, depending on the desired roast level. During roasting, the beans undergo several chemical and physical changes, such as:

• The beans lose moisture and weight and expand in size and volume.
• Depending on the roast level, the beans change from green to yellow to brown to black.
• The beans develop hundreds of flavor and aroma compounds, such as sugars, acids, oils, and gases, through the Maillard reaction, caramelization, and Strecker degradation.
• The beans crack or pop, indicating pressure and water vapor release. The first crack occurs around 350°F to 400°F, and the second crack occurs around 430°F to 450°F.
• The beans excrete oils to the surface, giving them a shiny appearance.

The roasting process can be done using different types of equipment, such as drum roasters, air roasters, popcorn poppers, or even frying pans. The roasting process can also be controlled by adjusting the beans' temperature, time, airflow, and agitation. The roaster can monitor the roasting process by using sight, sound, smell, and taste and instruments like thermometers, timers, and scales.

What are the different types of coffee roasts?

There are four general categories of coffee roasts: light, medium, medium-dark, and dark. Each category has a different flavor, color, and caffeine level. However, there is no universal standard for naming or measuring coffee roasts, so other roasters may use other terms or scales to describe them. Here are some common characteristics and examples of each roast category:

• Light roasts: Light roasts are roasted for the shortest time, usually until the first crack or slightly after. They are golden brown and have a dry surface, with no oils visible. They have the highest acidity and caffeine content and the most original flavors of the bean. They also have a light body and a sour, citrusy, floral, or grassy flavor. Some examples of light roasts are Cinnamon, New England, half-city, and Fair City.
• Medium roasts: Medium roasts are roasted until the first crack ends or the second crack begins. They have a medium brown color and a dry or slightly oily surface. They have a balanced acidity, caffeine content, and a mix of origin and roast flavors. They also have a medium body and a sweet, fruity, nutty, or caramel flavor. Some examples of medium roasts are city, American, regular, and breakfast.
• Medium-dark roasts: Medium-dark roasts are roasted until the middle or end of the second crack. They have a dark brown color and a moderately oily surface. They have a low acidity and caffeine content and a dominant roast flavor. They also have a whole body and a rich, bittersweet, spicy, or chocolatey flavor. Some examples of medium-dark roasts are the entire city of Vienna, light French, and creamy espresso.
• Dark roasts: Dark roasts are roasted until the end of the second crack or beyond. They have a very dark brown or black color and oily surface. They have the lowest acidity, caffeine content, and a smoky, burnt, or charred flavor. They also have a heavy body and a bitter, pungent, or ashy flavor. Some examples of dark roasts are French, Italian, espresso, Turkish, and dark French.

How to choose the best roast for your coffee?

The best roast for your coffee depends on your personal preference and the brewing method you use. Generally, lighter roasts are better for manual or drip methods, such as pour-over, Chemex, or French press, because they highlight the complexity and nuances of the coffee.

Darker roasts, such as espresso, moka pot, or AeroPress, are better for pressure or immersion methods because they produce a more robust and consistent extraction. Medium roasts are versatile and can work well with any brewing method.

However, there is no right or wrong way to enjoy your coffee, and you can experiment with different roasts and methods to find your favorite combination. The most important thing is to use fresh, high-quality beans and to grind and brew them properly.