A grinder is overheating and hard to calibrate. What is the most likely cause?

When a grinder is overheating and difficult to calibrate, the condition of the grinder's blades or burrs is a significant factor. Worn blades or burrs can lead to inefficient grinding, resulting in the motor working harder to produce the desired grind size. This extra effort can cause the grinder to overheat as the friction generated during the grinding process increases.

Moreover, when burrs are no longer sharp, they cannot cut through the coffee effectively, which can lead to uneven grind sizes and an inability to achieve the desired extraction results. The resistance created by worn burrs means the grinder may also struggle to produce consistent results, making calibration challenging.

In contrast, issues such as being overloaded with coffee, incorrect plugging, or overly high settings might lead to other performance issues, but they are less likely to cause both overheating and calibration difficulties directly related to the grinding quality. Thus, assessing the condition of the grinder blades or burrs is essential to resolve these specific symptoms.