  We cast the non--isentropic Einstein--Euler system into a symmetric
hyperbolic form. Such systems are very suited to treat initial value problems
of hyperbolic type. We obtain this form by using the pressure $p$ and not the
density $\rho$ as a variable. However, the system becomes degenerate when the
pressure $p$ approaches zero, and in these cases we regularise the system by
replacing the pressure with an appropriate new matter variable, the Makino
variable.
