Maillard Reaction (Roasting Phase)

Category: science

A chemical reaction between amino acids and reducing sugars that occurs during coffee roasting, defining the bean's foundational flavor profile.

The Maillard reaction begins inside the roasting drum when the bean temperature crosses approximately 300°F (149°C), causing the green beans to turn yellow and then distinct shades of brown. This process synthesizes hundreds of aromatic compounds and complex melanoidins, directly determining the sweetness, body, and savory notes of the final roast prior to the bean reaching "first crack."

Common Examples

• Our roaster automation script logs thermal telemetry to track the duration of the Maillard reaction phase down to the millisecond.
• Extending the Maillard reaction inside the drum reduces perceived acidity while amplifying the deep, nutty undertones of the single-origin bean.