A challenge unique to psychology is objectively capturing ephemeral subjective states during controlled experiments. Large bodies of literature use metacognitive probes and self-reports in order to measure states of knowing, perceived progress, as well as the onset of phenomenologies such as surprise or insight. Here we evaluate the usefulness of a visceral measure—the dynamometer—in a problem solving context to detect feelings of progress and insight experiences. The continuous measure of hand grip strength provides multiple data points per second and effectively captures the onset of insight experiences in real-time, and maps onto other measures showing convergent validity. Our results highlight the importance of viewing metacognitions during problem solving and insight moments as dissociable events that show different behavioural outcomes. We also found evidence that the participants were embodying the intensity of the insight experience, despite not being instructed to do so. The dynamometer may be a useful tool in any context where metacognitions are monitored continuously, and is particularly well suited for research in problem solving and insight.