What situations often occur during the roasting process? What kind of coffee flavors result from improper roasting?

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FrontStreet Coffee's Overview of Common Situations in the Coffee Roasting Process

Coffee roasting is the process of subjecting green coffee beans to specific temperatures to remove excess moisture from the beans, allowing certain components within the coffee beans to transform into caramelized sugars and flavor oils. Roasting is an essential stage for flavor development in coffee beans. The flavor compounds in coffee must undergo roasting to fully express their unique characteristics.

Underbaked Coffee

Underbaked coffee typically carries distinct astringency and grassy flavors, originating from defective beans or roasting too quickly at low temperatures, resulting in insufficient dehydration of the bean core, causing underbaking.

Burnt Coffee

Burnt coffee is invariably caused by excessively high surface temperatures. Whether it's from starting the roasting process with too much heat that causes the beans to burn, severely burnt beans emit a tar-like aroma when broken open. The bean surface predominantly shows black spots, and the coffee structure becomes loose and brittle.

Uneven Roasting

There are many factors that contribute to uneven coffee roasting. For example, inconsistent bean sizes, insufficient dehydration and development in the early stages can result in inconsistent colors when coffee beans enter the crack development stage. Additionally, roaster blade design and overloading during roasting can all potentially cause uneven coffee roasting.

Extreme Roasting

Many people pursue coffee flavors, body, or bitter tastes to an extreme, roasting coffee very light or very dark while blindly seeking their personal preferences. At this point, roasting should be based on the individual characteristics of the coffee beans—such as their hardness, particle size, and other fixed traits—rather than blindly taking extreme routes with coffee flavors, creating a significant mismatch between the coffee's taste and its essential nature.