11/01/2025
Coffee beans are indeed green when harvested but turn brown during processing and roasting.
Why Green Coffee Beans Turn Brown
1. Chlorophyll breakdown: Green coffee beans contain chlorophyll, which gives them their green color. During processing and roasting, chlorophyll breaks down, revealing hidden pigments.
2. Enzymatic reactions: Enzymes within the bean, like polyphenol oxidase, trigger chemical reactions that change the bean's color.
3. Maillard Reaction: Roasting initiates the Maillard reaction, a chemical reaction between amino acids and reducing sugars, producing new flavor compounds and browns the beans.
