| Physical Changes During Coffee Roasting |

The roasting process significantly impacts the flavor and causes substantial physical changes in coffee beans. These changes, particularly bean expansion and cracking, play a crucial role in determining the final flavor profile of the coffee.

1. Bean Expansion:

• First Crack: The "first crack" occurs as the beans are heated and the water inside them turns into steam, causing the beans to expand and crack. This is a critical phase, marking the transition from green to roasted coffee.

• Second Crack: At higher temperatures, the "second crack" happens, indicating further structural changes. This crack is less intense than the first and signifies the breakdown of the bean's cellulose structure, leading to the formation of oils on the surface and a darker roast.

2. Temperature's Impact on Bean Expansion:

• Lower End Temperatures: When the roasting process is stopped at lower temperatures, the beans undergo less expansion and cracking. This results in a lighter roast, preserving more of the original flavors and structure of the beans. The coffee retains higher acidity and a lighter body, with more pronounced floral and fruity notes. For Arabica beans, which are typically roasted at lower end temperatures, this approach helps maintain their delicate flavors and nuanced profiles.

• Higher End Temperatures: Extending the roast to higher temperatures leads to more extensive expansion and cracking. The beans become darker, and the roast develops more pronounced flavors due to the increased caramelization and Maillard reaction. This process also introduces bitter compounds that balance the sweetness. This method is often employed for Robusta beans, including Fine Robusta, which benefit from higher roasting temperatures to develop their full-bodied and robust flavor profiles.

The physical changes during coffee roasting, particularly bean expansion and cracking, play a crucial role in determining the final flavor profile of the coffee. Lower end temperatures result in lighter roasts with preserved original flavors, while higher end temperatures lead to darker roasts with more complex flavors.

Understanding and controlling these physical changes and temperature adjustments allows roasters to bring out the best in both Arabica and Fine Robusta coffees, delivering a diverse range of flavors to suit different preferences. By mastering these roasting techniques, one can achieve the perfect balance of acidity, body, and aroma, whether aiming for the subtle nuances of a light-roasted Arabica or the rich, full-bodied experience of a well-roasted Fine Robusta.

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