What is "Tip" or "Scorch" in roasting?

In the world of professional coffee roasting, defects like tipping and scorching are clear indicators that the energy application during the roast was not properly managed. These are not just aesthetic issues; they represent a failure to control the heat transfer, which ultimately impacts the flavor profile of the final cup. A roast defect is defined as a repeatable sensory or physical fault that prevents the coffee from reaching its intended expression.

Scorching typically happens when the drum temperature is too high at the start of the roast. As the beans tumble, they make contact with the hot metal surface of the drum, causing the outer edges or flat faces of the beans to char. This creates a burnt, bitter flavor that can mask the delicate origin characteristics of the coffee. It is a common issue when a roaster tries to push too much heat into the beans too early.

Tipping, on the other hand, is more specific to the bean's anatomy. The 'tip' of the coffee bean—the area where the embryo would have germinated—is physically weaker and more porous than the rest of the seed. When a roaster applies high heat too rapidly, this soft spot absorbs energy faster than the surrounding bean structure, causing it to char or 'tip.' This defect is often linked to the density and growth altitude of the coffee, as higher-density beans may react differently to heat.

To avoid these defects, roasters focus on managing the rate of rise and ensuring even heat distribution throughout the drum. Visual inspection after the roast is the first line of defense; by spreading beans on a light surface, you can easily spot the dark, charred marks characteristic of these faults. In practice, preventing these issues requires a disciplined approach to heat management, ensuring that the energy applied is sufficient to develop the bean without overwhelming its physical structure.