What You Need to Know
During char‑toasting, free amino acids such as leucine and phenylalanine react with reducing sugars to form pyrazines and furans, while the high temperature oxidizes cacao butter lipids to produce volatile aldehydes (hexanal, nonanal) and lactones that enhance buttery aroma. Controlled exposure (≈225 °C, 3 min) maximizes desirable aroma while preventing polyphenol over‑polymerization that leads to bitterness, and also reduces moisture for better storage.
The Science
Primary Reaction
Maillard reaction and lipid oxidation