May 17, 2024 4 min read


Coffee roasting is a process that transforms the chemical and physical properties of green coffee beans into roasted coffee products. The roasting process produces the characteristic flavor of coffee by causing the green coffee beans to change in taste. Coffee roasting is a complex process that significantly influences the flavour of the final product. 



Coffee beans need to go through the roasting process for several important reasons:

  1. Flavour Development: Roasting is crucial for developing the complex flavours we’ve come to  associate with coffee. The process transforms the beans' physical and chemical properties, causing them to expand and change colour. This is where the beans' aroma and flavour are brought out.
  1. Solubility: Roasting makes the beans soluble enough to be brewed. Unroasted beans are hard and not soluble, making them unsuitable for coffee brewing.
  1. Transformation: The roasting process is what turns the green coffee beans into the brown or dark beans that we grind and brew. It's a transformation that's essential for converting the raw beans into the product we all know as coffee.

Without roasting, coffee beans would not have the taste, aroma, or solubility required to make the delicious beverage enjoyed by millions around the world. It's a fascinating process that combines tradition, technology, and craftsmanship to create a variety of flavours from a single type of bean.


There are four general categories of coffee roasts: light, medium, medium-dark, and dark. Each of these roast levels produces a different aroma, appearance, and flavour.

  1. Light Roasts: Light roasts are roasted for the least amount of time. They generally reach an internal temperature of 180°C to 205°C right after the first crack occurs. These beans tend to not have the oils on them because they haven’t been roasted at a high enough temperature. Light roasts have the most caffeine (by volume) and the most acidity. The acidity in light roasts is often accompanied by a citrus or lemon tone.
  1. Medium Roasts: Medium roasted coffee reaches internal temperatures of 210°C-220°C. This is after the first crack and just before the second one occurs. They have a little bit more body than a light roast and less acidity.  Medium roasts are what the average Canadian coffee drinker is used to. These roasts are considered to have balanced flavours.
  1. Medium-Dark Roasts: Beans roasted to medium-dark reach an internal temperature of 225°C – 230°C. This is during or just after the second crack. This roast will also start showing the oils on the beans’ surface because the temperatures are high enough. These roasts have a richer, fuller flavour, more body, and less acidity.
  1. Dark Roasts: Dark roasts are roasted at high temperatures and for a longer time, which results in a darker color, a shiny surface due to the oils, and a bitter taste. They have less acidity and a heavier body compared to lighter roasts.

The roasting process can be done using various techniques such as drum roasting, air roasting, and pan roasting. Each method offers a unique way to control the roasting process and can result in different flavours and aromas.


There are several methods of coffee roasting, each offering a unique way to control the roasting process.

Drum Roasting: This is a traditional method that offers remarkable control over each batch. In drum roasting, a metal cylinder or sphere containing the coffee is rotated above a source of heat such as charcoal, gas, or electricity. The tumbling action of rotation ensures that all beans are roasted evenly.

    Advantages: Drum roasting offers remarkable control over each batch. It provides rich, full-bodied flavours, ideal for dark roasted coffee.

    Disadvantages: Drum roasting can be time-consuming and requires a lot of attention to ensure even roasting. It also requires a significant amount of heat, which can lead to higher energy consumption

    Air Roasting: Air roasting provides a cleaner taste by using hot air to ensure even heat distribution. In many modern roasters, hot air is propelled by a blower into a rotating metal cylinder containing the coffee.

      Advantages: Air roasting provides a cleaner taste by using hot air to ensure even heat distribution. It’s great for highlighting unique bean characteristics.

      Disadvantages: Air roasters can be more expensive than other types of roasters. They also tend to roast beans more quickly, which can make it harder to control the roast level.

      Pan Roasting: Pan roasting is an artful, hands-on approach that connects the roaster to the traditional roots of roasting. In the oldest method of roasting, a metal cylinder, or sphere, containing the coffee is rotated above a source of heat such as charcoal, gas, or electricity.

        Advantages: Pan roasting allows for a high level of control and can be done with minimal equipment.

        Disadvantages: Pan roasting can be labour-intensive and requires constant attention to prevent the beans from burning. It can also be difficult to achieve a consistent roast across all beans.

        Regardless of the method used, the coffee, after leaving industrial roasters, is rapidly cooled in a vat, where it is stirred and subjected to cold air propelled by a blower. Good-quality coffees are then sorted by electronic sorters to separate those beans from the ones either too light or too dark roasted, and the ones that are roasted badly.


        The type of roast significantly affects the flavour, aroma, and body of the coffee. Understanding these differences can help you choose the right roast for your coffee taste preferences.

        Note that the flavour of the coffee also depends on the origin of the beans and the brewing method used. Therefore, it's always a good idea to experiment with different beans and brewing methods to find your perfect cup of coffee. 

        Faema Canada in Montreal offers  premium quality coffee in a variety of roast and select blends imported from Italy that were hand-picked for their excellence and authentic taste, including a house blendprepared in Montreal. You can also find everything you need to make your next perfect cup of coffee including a wide selection of espresso machines at all price points.