Estimation of the mass of the reprocessing gas responsible for the emission of the spectral lines in TDEs in order to investigate if the recombination time (τ_rec ≈ (n_eα_B)⁻¹, where n_e is the electron density and α_B is the case B recombination coefficient) could be responsible for the lags that we discover. We assume its geometrical shape is a sphere (as the simplest approximation) and that the material’s composition is solar-like and fully ionized. We perform three calculations with varying electron densities (which could result to the observed t_lags) that in turn yield three total number densities n_tot. For all the cases we get a sensible fraction of a solar mass (2.5−10%) assuming the radius of the line emitting region is on the order of 10¹⁶ cm.