Roasting: The beans are heated, causing chemical changes that develop the flavors, aromas, and colors.
First Crack: The beans expand and crack, releasing steam and gases. This marks the beginning of the roasting process.
Development: The beans continue to roast, undergoing Maillard reaction (browning) and caramelization, which adds complexity and sweetness.
Second Crack: A second, quieter cracking occurs, indicating a deeper roast level with more oils and bitterness.