The article ‚Temperature distribution in a gas-solid fixed bed probed by rapid magnetic resonance imaging‚ has been recently published in Chemical Engineering Science and a preprint is also available at arxiv. In this study, we show how to turn MRI into a 3D thermometer and use it to investigate the thermal dynamics in a model fixed bed subjected to heat flow. This study is part of a collaboration between Hamburg University of Technology and ETH Zurich.