This paper presents analysis of hypersonic base flows using the detached eddy simulation (DES) methodology. Unlike Reynolds-averaged Navier-Stokes (RANS) simulations, DES computes the dominant unsteady motion in the three-dimensional flow behind a vehicle, and thus results in a more realistic flow field than RANS. Simulations are performed on carefully designed DES grids and the effect of grid refinement in the focus region is studied. At the current conditions the flow in the near wake is transitional. Successive grid refinement in this case reduces the magnitude of the eddy viscosity such that the DES solution on the finest mesh approaches direct simulation without a turbulence model. In the absence of significant eddy viscosity, lowering of numerical dissipation is essential to achieve grid-converged solution.