What is Coffee Bean Roasting Curve and What's the Best Roast Level for Kenya Coffee

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FrontStreet Coffee Roasting Curves: Kenya Coffee Roasting Curve Sharing

The vertical axis represents temperature, while the horizontal axis represents time. The middle section shows the line indicating how the temperature of green beans changes over time during the roasting process. The values at the circular points represent the current drum temperature. The green bean temperature is lower than the preset drum temperature, so when beans are loaded, the temperature curve will inevitably show a relative drop. When the internal and external temperatures of the coffee beans begin to balance, the curve starts to rise again, and that point is called the "turning point."

As the temperature rises during roasting, the curve gradually climbs upward, and the internal fibers of the coffee beans begin to change. The cells of the coffee beans are broken down, and you start to hear crackling sounds - this marks the arrival of the "first crack."

The time when the beans are discharged is determined by the roaster. After discharging, cupping is performed to evaluate the flavor of the roasted coffee beans. Based on the cupping results, roasting adjustments are made. This also serves as a way to test one's roasting skills.

Kirinyaga Region

Yangjia 800N Roasting Machine (500g batch size)

Preheat the drum to 170°C, set the damper to 3, and heat to 100. The turning point occurs at 1'45". When the drum temperature reaches 140°C, maintain the heat and open the damper to 3.5. When the drum temperature reaches 143.3°C, the bean surface turns yellow, the grassy aroma completely disappears, and the beans enter the dehydration stage.

At 7'32", ugly wrinkles and black spots appear on the bean surface, and the toast aroma clearly transforms into coffee aroma. This can be defined as the prelude to the first crack. At this point, listen carefully for the sound of the first crack. The first crack begins at 8'20", reduce the heat to 50, and adjust the damper to 4 (be very careful when adjusting the heat - don't reduce it so much that the cracking sound disappears). Develop for 1'50" after the first crack, then discharge at 192°C.

Kirinyaga Region Flavor Profile:

Lemon, floral notes, tomato, citrus, cane sugar, raspberry, herbal, cream - overall, the mouthfeel is relatively refreshing and clean.

Important Notice :

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