What You Need to Know
During toasting at ~200–220 °C, Maillard reactions generate phenolic aldehydes and other Maillard products that coat the husk and impart a smoky aroma. The subsequent steaming at ~100 °C for 45–60 minutes gelatinizes the starch in the masa, keeping it moist while allowing the husk’s charred flavor to permeate the filling.
The Science
Primary Reaction
Maillard reaction and phenolic aldehyde formation during toasting; starch gelatinization during steaming