Roasting coffee is cooking green coffee beans. During this process, the beans undergo many changes in their chemical and physical properties. A fundamental transformation takes place, what is called the Maillard reaction. This reaction - which is in fact a series of reactions - is responsible for the color change and the development of aromas when cooking food. It's the same reaction that happens when we roast our bread in the morning, for example.
During cooking, amino acids and simple sugars turn into new molecules that bind to each other. As cooking progresses, the new molecules created by the interaction between amino acids and sugars in turn transform into new molecules, producing an increasingly dark color and giving off more and more intense aromas. Beyond a certain degree of roasting, the beans undergo a decomposition responsible for the burnt taste, bitterness - in part - and its black color. The aromatic spectrum narrows and smoky, even charred notes are predominant. A dark roast is sometimes used to hide the defects of a lower quality coffee.
Consumers have long had to settle for only two coffee options: "velvety" and "full-bodied". We also often heard of "brown" or "black" coffee, again referring to the degree of roasting, without more nuances or explanations. These terms are still used by many roasters, but in the specialty coffee world, there is more talk of light, medium and dark roasting. In addition, the tasting notes are brought to light more by the roasters. Influenced by a multitude of factors, including the origin, varieties, different grain processing methods, roasting and extraction, these notes help consumers better guide their choice according to their preferences. The development of the specialty coffee industry has enabled a better understanding of the influence of the terroir on the beans, the advancement of grain processing techniques and the achievem