1. Overview & Physics
Melanoidin Synthesis
The Maillard reaction begins around 150째C. Nitrogen-containing amino acids bind with sugars to create volatile aromatic molecules. This process generates hundreds of new compounds, including furans (caramel notes) and pyrazines (nutty notes). It also produces brown pigments called melanoidins, which build the body and viscosity of espresso crema.
Flavor Tuning
Baristas can manipulate this phase by extending the roast time during yellowing to boost sweetness and body in espresso beans.
2. Practical Calibrations
Managing this requires measuring indicators in real time. Adjust grind size, water dynamics, and flow parameters incrementally. Change only one variable at a time to ensure clean results and isolate target parameters.
Barista Action Checklist
- Weigh dry grounds dry dose exactly to 0.1g.
- Calibrate water temperature using PID sensors.
- Target correct brew ratios (e.g. 1:15 for filter, 1:2 for espresso).
- Swirl or stir to ensure even saturation during extraction.
- Record extraction time and evaluate flavor notes subjectively.
Frequently Asked Questions
What is the Maillard reaction in coffee?
It is a chemical reaction between amino acids and reducing sugars that occurs under heat, generating roasted aromas and brown melanoidins.
How does roasting time affect Maillard flavors?
A longer Maillard phase (drying to first crack transition) builds complex body, sweetness, and nutty profiles, while reducing sharp fruit acidity.
