What You Need to Know
Dry roasting triggers Maillard reactions between reducing sugars and amino acids at 140–165 °C, while caramelization of sugars begins above 160 °C. Oil roasting uses 180–200 °C, with oil acting as a heat conductor that reduces surface temperature and limits oxidation, carrying flavor compounds. Steam roasting injects steam at 100 °C before applying dry heat (~200 °C), gelatinizing starches and delaying Maillard until moisture is reduced, yielding a moist yet browned surface.
The Science
Primary Reaction
Maillard reaction and caramelization (dry), oil-mediated heat transfer and oxidation control (oil), steam gelatinization and delayed Maillard (steam)