What is the chemistry after roasting coffee

Chemical changes during the roasting process

Roasting ensures that both special coffee aromas and the characteristic taste and smell of the coffee are formed. These are achieved through numerous primary and secondary chemical reactions, which are very complex and therefore in some cases not yet fully explored. The green coffee itself already contains numerous substances that are converted into over 1000 aromatic compounds through chemical reactions, only some of which are known.

The most important chemical process is the Maillard reaction, which is a non-enzymatic tanning reaction. The amino acids as well as proteins and peptides in the raw coffee are converted into new compounds with reducing sugars by means of the effect of temperature. The Maillard reaction involves a multi-stage reaction that creates color and flavoring substances. In addition to this reaction, other chemical reactions take place during the roasting process, such as hydrolysis, caramelization, oxidation, pyrolysis and decarboxylation. Through these processes, many taste properties are achieved that can enrich coffee with body, sweet, chocolaty and nutty components.

In addition to the development of these taste components, the type, duration and temperature of the roasting can also control the acidity. This plays a very important role for high-quality coffee, as the taste can be expanded to include fruity and flowery components.