In this brief article we describe a simple apparatus that can produce sufficient quantities of thermally stressed complex fluids (such as fuels) to allow a full range of thermophysical property measurements to be performed on the resulting fluid. The apparatus operates in a continuous rather than batch mode, and consists of a high pressure pump, a reactor section, a quench, and a collection vessel. The apparatus is capable of operation to 55 MPa, 600 degrees C, with residence periods that are chosen on the basis of a wide range of fluid flow rates. Automation of the temperature and pressure control allows for safe, unattended operation. We have used this apparatus to generate thermally stressed rocket kerosene (RP-1 and RP-2) at 475 and 510 degrees C, and at a pressure of 17 MPa. We have verified that the thermally stressed fluid is comparable in composition to fluids that result from careful thermal decomposition kinetics measurements that are done in ampule reactors.