Interest in chiral versus racemic amino acid forms stems from their different solid-state properties associated to the packing arrangement that leads to starkly different physical behavior. Here we focus on the different dynamic properties of the chiral (L-form) and racemic (DL-form) crystals of serine, (C3H7NO3). Measuring incoherent inelastic neutron and Raman scattering over a wide temperature range we could assess a subtle dynamical transition in L-serine near 150 K. The difference in the dynamic properties of the crystals of L- and DL-serine evidenced from our spectroscopic studies is in a good agreement with the different C p (T ) dependences and different structural strain of the two forms on cooling. Despite a higher bulk density, the molecular fragments in the crystals of L-serine are more dynamic than in DL-serine, and this manifests itself in the incoherent inelastic neutron and Raman spectra, as well as in a higher heat capacity, a higher thermal expansion coefficient, or in the NMR-spectra.