To summarize, roasting has a major impact on the final taste of coffee. Roasting is the stage in our seed to cup journey where green coffee is transformed from an agricultural product into the beans we use for brewing.
Does roasting change the mass of coffee beans?
Why does dark-roasted coffee taste different?
Bean density decreases continuously, more gases are developed as time passes, and in a very dark roast, you may see oil migrate to the surface of the beans. These developments go some way to explaining why a dark-roasted coffee tastes different to a light-roasted one, but there are also significant chemical transformations that impact profile.
What does roasted coffee smell like?
Sulfur-containing compounds, including 2-furfurylthiol. Some of these have an aroma that is commonly described as “roasted coffee” but there are others that don’t smell as appealing in isolation. For example, methanethiol smells like rotten cabbage. Guaiacol, which has smoky, spicy tones.