What impact does a higher moisture content have on green coffee beans during roasting?

• A. It enhances sweetness in the flavor
• B. It causes uneven roasting and inconsistencies in flavor
• C. It prevents the beans from browning
• D. It reduces the roasting time

Answer: (B)

A higher moisture content in green coffee beans significantly impacts the roasting process, leading to uneven roasting and inconsistencies in flavor. When beans contain more moisture, the roasting environment becomes less stable. The water in the beans must first evaporate before the actual roasting can take place, which can result in some areas of the batch roasting at different rates. This uneven heat distribution can lead to certain beans being under-roasted while others may be over-roasted by the time the desired roast level is achieved, causing inconsistencies in flavor profile across the batch.

Roasting is a complex chemical process that involves various reactions, and moisture plays a critical role. When beans have high moisture content, it can delay the onset of the Maillard reaction and caramelization, essential for developing the desired sweetness and complex flavors. Thus, while higher moisture may seem advantageous in preserving freshness, it complicates the roasting process and affects the uniformity of the roast, resulting in flavor inconsistencies.